I slept . . . . . . . . the speech. A. during B. in C. by D. on

during
in
by
on

The correct answer is A. during.

The other options are incorrect because:

  • B. in is used to indicate a location or position. For example, “I slept in the bed.”
  • C. by is used to indicate a means or method. For example, “I slept by counting sheep.”
  • D. on is used to indicate a surface or location. For example, “I slept on the couch.”

The word “during” is used to indicate a period of time. In this case, the speaker is saying that they slept during the speech. This means that they were asleep while the speech was being given.