Which of the following groups in NOT mentioned as migrants in the passage（）

单项选择题We can learn from the passage that Blackpool used to（）

A．have as many beaches as Luxemburg.
B．have seriously polluted drinking water.
C．boast some imposing seafront sights.
D．attract few domestic holiday makers.

单项选择题What Blackpool's beaches strike visitors most is their（）

A．emptiness.
B．cleanliness.
C．modernity.
D．monotony.

单项选择题According to Kingsley Davis, migration occurs as result of the following reasons EXCEPT（）

A．human adaptability.
B．human evolution.
C．cultural differences.
D．inter-group inequalities.

单项选择题According to the passage, which of the following is NOT the writer's opinion（）

A．Countries paid a heavy price for whichever measure taken.
B．Countries all found themselves in an economic dilemma.
C．Withdrawal of foreign capital resulted in the crisis.
D．Most governments chose one of the two options.

单项选择题Which of the following statements is INCORRECT（）

A．Migration exerts a great impact on population change.
B．Migration contributes to mankind's progress.
C．Migration brings about desirable and undesirable effects.
D．Migration may not be accompanied by human conflicts.