When Her Income Falls from $50,000 to $20,000,Arianna Increases Her

When her income falls from $50,000 to $20,000,Arianna increases her monthly purchase of hamburger from 20 pounds to 35 pounds.From the midpoint method,Arianna's income elasticity of demand for hamburgers is

A) -1.57.
B) -0.63.
C) 0.54.
D) -0.85.
E) 1.57.