Which word is closest in meaning to the word "conjecture"?

It's a word to use when you are not sure of something and have to "guess or surmise."  

hope it helps

Conjecture is a noun that is defined as "the formation or expression of an opinion or theory without sufficient evidence for proof.  An opinion or theory so formed or expressed; guess; speculation."

Some synonyms of conjecture include: guess, presumption, suposition, conclusion, hypothesis, inference.

As a verb, conjecture means to conclude or suppose from grounds or evidence insufficient to ensure reliability.

So, the closest word in meaning would be guess.

i think the answer is c.  

- "in the declaration of independence, it is stated that all people have certain rights that can't be taken away. when the government fails to protect these rights, the people have no choice but to remove that government and replace it with a government that will do its job and protect the people's rights."