Final answer:
A cosigner is the person who agrees to take responsibility for payment if the original borrower cannot repay the loan. So the correct answer is option C.
Step-by-step explanation:
The term that BEST describes the person who agrees to take responsibility for payment if Silvia cannot is a cosigner. A cosigner is another person or firm who legally pledges to repay some or all of the money on a loan if the original borrower does not. In this case, the electric company is requiring Silvia to find a cosigner as a condition for signing up for electric service.