Replace the underlined tense form with the correct option, if necessary:The moon is revolving around the sun.

The correct answer is Option A: revolves. The sentence is in the present continuous tense, which indicates an action happening at the present moment. The present continuous tense of the verb "revolve" is "revolves," so it should replace the underlined tense form "is revolving."

The other options are not correct:
B. has revolved (Incorrect) - This is in the present perfect tense, which is not suitable for the context of the sentence.
C. revolved (Incorrect) - This is in the simple past tense, which is not suitable for an ongoing action.
D. no change (Incorrect) - The original underlined tense form "is revolving" is not correct in this context; it should be changed to "revolves" in the present simple tense.