She wanted to know whether butterflies drank water.

The correct answer is A. She wanted to know “Do butterflies drink water?”.

The other options are incorrect because:

• B. She asked, “Do butterflies drink water?” is incorrect because it is a statement, not a question.
• C. She asked, “Did butterflies drank water?” is incorrect because it uses the past tense, when the speaker is asking about the present.
• D. “Does butterflies drinks water?”, she asked. is incorrect because it uses the singular verb “drinks” with the plural subject “butterflies”.

The speaker is asking whether butterflies drink water, so the correct question would be “Do butterflies drink water?”.