You chose: Arabella should marry Glanville
This is exactly the ending that occurs in the novel -- after being "cured," Arabella and Glanville get married. Motooka argues that this ending was "disappointing" for many readers and takes "what had seemed a glorious feminist spark" and "fizzles" that out "into an unremarkable marriage" (Motooka 251). While this ending may be rather pedestrian and expected of an 18th century novel, Glanville and Arabella do have an established friendship and mutual respect/interest, so the novel certainly sets up their future relationship.