Christina needs a loan for $10,000 to complete her master's degree. She receives a 5 year, $10,000 loan from People's Bank and Trust (PB&T), but she needs her mother to co-sign on the loan because she cannot qualify for the loan on her own. Her mother is a long-time customer of PB&T and agrees to co-sign the loan. Her mother receives no consideration for co-signing on the loan and is pleased her daughter is advancing her education. Three months into the master's program, Christina decides to quit and travel the world. Unknown to her mother, Christina goes back to PB&T and modifies the loan contract, obtaining an additional $10,000 and extending the loan for 3 more years. Which of the following is correct as it relates to Christina's mother's obligations under the loan?
A. Christina's mother is a guaranty on the loan and is only secondarily liable if Christina defaults.
B. Christina's mother is a guaranty on the loan and can demand that PB&T collect from Christina first.
C. Christina's mother is a surety on her daughter's loan but can assert her daughter's incapacity as a defense.
D. Christina's mother is a surety on her daughter's loan but is completely discharged because the loan contract was modified without her consent.