Read the sentence and answer the question.

pilots flew on two-person gemini missions and apollo flights to the moon these were the last air force officers to serve as pilots.

which correctly shows where a semicolon is needed in the sentence?

a.
pilots flew; on two-person gemini missions and apollo flights to the moon these were the last air force officers to serve as pilots.

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.

c.
pilots flew on two-person gemini missions and apollo flights to the moon these were; the last air force officers to serve as pilots.

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.