At many municipal golf courses, local residents pay a lower fee to play than other golfers do. One necessary condition for the golf course to be able to successfully price discriminate according to residency is that

a.they can check the identification cards of golfers.
b.local resident golfers and other golfers have the same price elasticity of demand to play at the municipal course.
c.there are many golf courses nearby from which golfers can choose.
d.they require all golfers to rent a cart