Mrs Smith is not pleased . . . . . . the new servant. A. with B. of C. at D. on

The correct answer is A. with.

The preposition “with” is used to express a relationship of association or connection between two things. In this case, Mrs. Smith is not pleased with the new servant. This means that she does not like the servant or is not happy with the servant’s performance.

The other options are not correct because they do not express a relationship of association or connection. The preposition “of” is used to express possession or ownership. The preposition “at” is used to express location or position. The preposition “on” is used to express a position on or above something.

In conclusion, the correct answer is A. with.