Answer:
A - accusations, exonerate.
Explanation:
Imputation is an accusation, and exculpate means to show or declare that someone is not guilty of wrong doing, which is basically the definition of exonerate.
The correct answer is becoming an astronomy researcher
For starters, it is the only appositive phrase. It is also non-essential because the sentence conveys full meaning even if it was removed.
The rich only want to get richer, and leave poor people in the dust, so they pay people off to keep them happy enough to shove the rest of us down.