In the litigation between Pringle and Doyle, which of the following constitutes the best defense for Doyle?
The facts do not establish a common building or development scheme for the entire subdivision.
Oscar's difficulty in selling with provisions relating to use establishes a change in circumstances which renders any restrictions which may once have existed unenforceable.
Enforcement of the restriction, in view of the change of circumstances, would be an unreasonable restraint on alienation. 
Since the proof (as stated) does not establish a danger of monetary loss to Pringle, Pringle has failed to establish one of the necessary elements in a cause of action to prevent Doyle from using his lot for business purposes. 