Answer:
This question is lacking options. Here are the options 
a. a void agreement because of the fraud involved. 
b. a voidable contract, one that Jack can void. 
c. a voidable contract, one that Jennifer can void. 
d. a void contract because of the UCC.
An the answer is b. a voidable contract, one that Jack can void. 
Step-by-step explanation:
A contract is an agreement, whether verbal or written that is legally binding between two people. 
A voidable contract is a an agreement between two parties that can be rendered unenforceable as a result of one of the following reasons. 
Failure by one or both parties to disclose a material fact , a mistake,, misrepresentation or fraud , undue influence or duress , one party's legal incapacity to enter a contract etc. 
In the case of Jenifer and Jack, the contract is voidable because Jack had been lied to by Jenifer, and Jack didn't know that the computer was a lemon. 
Hence the answer is B. a voidable contract, one that Jack can void.