She smiled . . . . . . . . my mistakes. A. on B. upon C. over D. at

The correct answer is D. at.

The word “at” is used to indicate a particular point in time or space. In this case, the speaker is saying that the woman smiled at the speaker’s mistakes. This means that she was looking at the speaker’s mistakes and showing an expression of amusement or pleasure.

The other options are not as appropriate in this context. The word “on” is used to indicate a surface or location. The word “upon” is a more formal version of “on.” The word “over” is used to indicate a position above or across something.

Here are some examples of how the other options could be used in a sentence:

• The cat sat on the mat.
• The king sat upon his throne.
• The bird flew over the tree.