She explained the solution to us . . . . . . . . a patient manner. A. in B. of C. at D. on

in
of
at
on

The correct answer is: in.

The preposition “in” is used to indicate a manner or way of doing something. In this case, the speaker is saying that the woman explained the solution in a patient manner. This means that she was calm and understanding, and took the time to explain things clearly.

The other options are not correct because they do not indicate a manner or way of doing something. The preposition “of” is used to indicate possession or association. The preposition “at” is used to indicate a location or time. The preposition “on” is used to indicate a surface or position.

Here are some examples of how the preposition “in” can be used to indicate a manner or way of doing something:

  • She spoke in a loud voice.
  • He acted in a friendly manner.
  • They worked in a careful manner.