A: Where’s Helen? B: She . . . . . . . . in the office. A. is sitting B. sit C. sitting D. sits

The correct answer is: A. is sitting

The verb “to sit” can be used in the present tense in three different ways:

• Simple present: This is used to talk about things that happen regularly or repeatedly. For example, “I sit at my desk every day.”
• Present progressive: This is used to talk about things that are happening right now. For example, “I am sitting at my desk right now.”
• Present perfect: This is used to talk about things that have happened recently or that have just happened. For example, “I have sat at my desk for an hour.”

In the sentence “Where’s Helen? She is sitting in the office,” the verb “is sitting” is in the present progressive tense. This is because the speaker is talking about something that is happening right now. Helen is currently sitting in the office.

The other options are incorrect because they are not in the present progressive tense. Option B, “sit,” is in the simple present tense. Option C, “sitting,” is the present participle of the verb “to sit.” Option D, “sits,” is the third person singular form of the verb “to sit.”

I hope this helps!