单项选择题

A.The modified data are not available on disk.B.The mod……

Two database users, Jack and Bill, are accessing the SupportCenter STAFF table of the SupportCenter DB database. When Jack modifies a value in the table, the new value is invisible to Bill. Which is the modified value invisible to Bill?（）

A.The modified data are not available on disk.
B.The modified data have been flushed out from memory.
C.The modified rows of the SupportCenter STAFF table have been locked.
D.Jack has not committed the changes after modifying the value.
E.Both users are accessing the database from two different machines.

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