Answer:
This all depends on context, but in general:
Neutral: Generally having a middle ground opinion rather than being on an extreme side.
Positive: Usually refers to one's attitude, optimism. Can also mean certainty.
Negative: Not positive, could be referring to pessimism or seeing the bad side of things.
Silent Spring by Rachel Carson was an environmental science book. It documented the negative effects the indiscriminate use of pesticides has on the environment, particularly the birds.
The book became the tool that awakened the public to the real harm that big industrial companies have been hiding from them. Thus, driving them to launch an environmental movement that aims to prohibit the indiscriminate use of pesticides, specifically DDT.
It would be C because a conjunction can stand alone
