Question

the root cred means trust or believe. what does the word incredulous mean?
unwilling to accept something as true
unwilling to do harm to others
unwilling to give something away
unwilling to engage in hostility

Explanation:

The root "cred" means trust or believe. The prefix "in - " often means "not". So "incredulous" should relate to not trusting or not believing, which matches "unwilling to accept something as true". The other options are about harming others, giving things away, or hostility, which don't relate to the root "cred".

Answer:

unwilling to accept something as true