Petro Refinery Asks Quality Bank for a Loan to Increase

Petro Refinery asks Quality Bank for a loan to increase its inventory. Quality requires Rose, Petro's president, to sign a personal guaranty to pay the debt if Petro defaults. Rose is a guarantor. The guaranty is required to be in writing because

A) the debtor has a right of redemption.
B) the co-signer has a right of contribution.
C) the main purpose rule applies.
D) the main purpose rule does not apply.