By 1999, astronomers had discovered 17 nearby stars that are orbited by planets
about the size of Jupiter
A: had discovered 17 nearby stars that are orbited by planet
B: had discovered 17 nearby stars with planets orbiting them that were
C: had discovered that there were 17 nearby stars that were orbited by planets
D: have discovered 17 nearby stars with planets orbiting them that are
E: have discovered that 17 nearby stars are orbited by planets
I understand why the present perfect is wrong but hoping an expert can explain the reasoning between the other three answer choices.
about the size of Jupiter
A: had discovered 17 nearby stars that are orbited by planet
B: had discovered 17 nearby stars with planets orbiting them that were
C: had discovered that there were 17 nearby stars that were orbited by planets
D: have discovered 17 nearby stars with planets orbiting them that are
E: have discovered that 17 nearby stars are orbited by planets
I understand why the present perfect is wrong but hoping an expert can explain the reasoning between the other three answer choices.












