If Christen Pays Dusty,does She Have Any Rights to Receive

If Christen pays Dusty,does she have any rights to receive reimbursement from Doug?

A) No, because she has no legal liability and is acting as a volunteer.
B) No, because only Christen is liable on the assignment.
C) Yes, but she would only be entitled to recover one half of the amounts because she and Doug are jointly liable to Dusty.
D) Only if Doug specifically agreed by contract when he accepted the premises to reimburse her.
E) Yes, Christen would have a right of reimbursement from Doug.