Answer: b. It is hard to manipulate expression given off.
Explanation: Expression given off are those observable characters we see people portray, that are non verbal and can be intentional but mostly are unintentional. This expression is easy to believe and trust because it describes the totality of the persons attitude, making it very difficult to manipulate, and not what the person has said. Humans can be very deceptive with their words, so it is more trustworthy to believe them with their actions.
Expression given are those intentional words people given. They are verbal, such as utterances, campaign speech and many more.