Fact Pattern 33-1Petro Oil Refinery Asks Quality Bank for a Loan

Fact Pattern 33-1Petro Oil Refinery asks Quality Bank for a loan to increase its oil inventory. Quality requires Robin, Petro's president, sign a personal guaranty to pay the debt if Petro defaults. Meanwhile, to sell fifty barrels of refined oil to Slick Lubricants, Inc., Petro asks its outside accountant Tina to co-sign a credit application.
-Refer to Fact Pattern 33-1.If Robin is a guarantor,then the guaranty is required to be in writing because of 

A)  ​the debtor's right of redemption. 
B)  ​the co-signer's right of contribution. 
C)  ​the creditor's transfer of possession. 
D)  ​the Statute of Frauds.