Answer: C. cannot avoid the contract because of economic duress or failure to read.
Explanation: Economic duress in contract happens when one of the party threatens to pull out or cancel a contract if the other party do not agree to his demand. It occurs when the other party is left without any other option and his stuck, but had to agree to the new terms of the contract.
In this case Ben signed the contract without reading it because he was sack for his current job, putting him in a tight situation.