在VFP中，空值是一种特殊的数据，用.NULL.或NULL表示。下列关于空值的表述中正确的是（）。

A、空值等价于空字符串、空格或数值0

B、函数ISNULL（.NULL.）的值与函数EMPTY（.NULL.）的值相同

C、将一个.NULL.值赋给字段或变量时，不改变该字段或变量原有的数据类型

D、变量A1的值为.F.，则表达式A1AND.NULL.的值为.NULL.

Woman: Oh, dear! I’m afraid I fail again in the national test. It’s the third time I took it.
Man: Don’t be too upset. I have the same fate. Let’s try a fourth time.
Question: What does the man mean（）。

A. He is sure they will succeed in the next test.

B. He did no better than the woman in the test.

C. He believes she will pass the test this time.

D. He felt upset because of her failure.