It was so nice . . . . . . . . them. A. by B. with C. of D. to

by
with
of
to

The correct answer is to.

The preposition to is used to express a feeling or emotion towards someone or something. In this case, the speaker is expressing their feeling of happiness or pleasure towards the people they are talking about.

The other options are not as appropriate in this context.

  • By is used to express a means or method. For example, “The letter was delivered by the postman.”
  • With is used to express a state of being or a relationship. For example, “I am friends with John.”
  • Of is used to express possession or a part of something. For example, “The book is of great value.”

I hope this helps! Let me know if you have any other questions.