Answer:
a. Olives
Explanation:
Olives came from Latin American and became a staple product of Italian cuisine.
My teacher tell me it's d. Coal
The opinions and prejudice of an author in writing.
I believe that those two elements greatly affect bias in history because we can never be 100% sure of everything that (may have) happened in history (especially farther in the past), so opinion can affect a historian's writings. Also, everyone is prone to some sort of prejudice, so this can also affect history.