D. Pilots flew on two-person Gemini missions and Apollo flights to the moon; these were the last Air Force officers to serve as pilots.
Explanation:
The sentence that correctly shows where is semicolon is needed in the sentence is option B. Pilots flew on two-person Gemini missions and Apollo flights to the moon; these were the last Air Force officers to serve as pilots. A semicolon is used after the word "moon" to separate two independent clauses in the sentence. Semicolons are typically used in compound sentences.
Answer:
Pilots flew on two-person Gemini missions and Apollo flights to the moon; these were the last Air Force officers to serve as pilots.
