Suppose We Postulate a Linear Demand Curve $Q ^ { d } = a - b P$

Multiple Choice

Suppose we postulate a linear demand curve $Q ^ { d } = a - b P$ and observe, through supply shifts, two points on the demand curve. At point A, P_A = 2 and Q^d_A = 6. At point B, P_B = 4 and Q^d_B = 2. The choke price for this demand curve is

A) 10
B) 2
C) 5
D) -2