Ray Bradbury became famous because _____________________.
In the above mentioned passage, the most appropriate answer for completing the sentence is Option D.
The passage describes Ray Bradbury, a well known name in the circuit of science fiction and thrillers. His work, The Martial Chronicle, is what made him leap into the winds of success at the age of thirty. It is mentioned in the initial part of the sentence itself, making it the most appropriate option for completing the same.
The other options A, B and C have never even once been mentioned in the passage above, and thus stand wrong for the sentence to be completed.