Respuesta :
Answer:
D. The history professor asked, “What famous event happened on April 4, 1968, in Memphis, Tennessee?"
Explanation:
There needs to be a comma between "asked" and the open quote to represent a pause and separate who asked the question, and the question itself; this rules out alternative B.
When presenting dates within a sentence, there needs to be a comma after the date to separate it from the rest of the sentence; this rules out alternatives A and C.
By process of elimination, the only possible alternative is D.