Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction.

Among the earliest telescopes were Galilean telescopes, modeled after the simple instrutments built by Galileo, the first person having used telescopes to study the stars and planets

A. having used

B. telescopes

C. modeled

D. were

Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.

After he ________ his homework, he went straight to bed.

A. has finished

B. was finished 

C. finished

D. had finished