According to the passage, NCLB mainly aimed to……

Margaret Spellings, the secretary of education, announced a pilot reform to the No Child Left Behind Act (NCLB), George Bush’s education law, which was passed in 2002 Up to ten states, she said, would be allowed to target their resources at the most severely struggling schools, rather than at the vast number needing improvement. The change drew a predictable mix of praise and censure. Above all, though, it was a reminder of utter inaction elsewhere.
Congress, which was supposed to re-authorize the law last year, has made little progress. On the campaign trail, concerns over Iraq and the economy have made education a minor issue. Contrary to appearances, the law’s main tenets are unlikely to be abandoned completely. But for the Democratic candidates in particular, a proper debate on NCLB is to be avoided like political quicksand.
Most politicians agree that the law has the right goals—to raise educational standards and hold schools accountable for meeting them. NCLB requires states to test pupils on math and reading from third to eighth grade (that is, from the ages of eight to 13), and once in high school. Some science testing is being added. Schools that do not make "adequate yearly progress" towards meeting state standards face sanctions. Pupils in failing schools can supposedly transfer to a better one or get tutoring.
Most also agree that NCLB has big flaws that must be fixed. Few pupils in bad schools actually transfer—less than 1% of those eligible did so in the 2003—04 school year. Teachers’ unions say the tests are focused too narrowly on math and reading, fail to measure progress over time and encourage "teaching to the test". They also complain that the law lacks proper funding. The Thomas B. Fordham Foundation, a conservative policy group, has exposed wide gaps in state standards. Test-data reflect this. In Mississippi 90% of fourth-graders were labeled "proficient" or better in the state reading test in 2006-07. Only 19% reached that level in a national test.
John McCain, the Republican presidential nominee, offers NCLB tepid support but fails to elaborate. At Democratic rallies, NCLB is little more than a whipping-boy. Hillary Clinton proclaims that she will "end the unfunded mandate known as No Child Left Behind". But though she and Barack Obama deride NCLB publicly, each endorses the idea of accountability. They favor using more sophisticated "assessments" in place of tests, want to value a broader range of skills, punish schools less and support them more. How these ideas would be implemented remains unclear.
Not surprisingly, more controversial proposals can be found among those not running for president. Chester Finn of Fordham thinks the federal government needs greater power to set standards, while states should have more leeway in meeting them. A bipartisan commission on NCLB has issued a slew of proposals. Particularly contentious is a plan to use pupils’ test scores to help identify ineffective teachers as in need of retraining.
Of course, standards alone do not improve education. Both Mrs. Clinton and Mr. Obama propose a host of new programs for schools, described on their websites if rarely on campaign. But accountability is likely to remain a big part of school reform. Last April a group of philanthropists announced a $60m effort to make education the top domestic issue of 2008. So far, it looks like money iii spent.
According to the passage, NCLB mainly aimed to

A．provide tests for pupils on maths and reading from third to eighth grade.
B．add some science testing in schools for pupils aged from 8 to 13.
C．enhance teaching standards which schools should be responsible for meeting.
D．transfer pupils in falling schools to a better one or get them some tutorin