The Demand for Watches Is Q = 1,000P ^-0

The demand for watches is Q = 1,000P ^-0.50I^-1.Assume that per capita income I is $5,000.At a price P of $50, the price elasticity of demand is

A) 2.50.
B) 1.0.
C) -1.
D) -1.50.
E) 0.50.