Consider the following demand function for good 'X': Q = 9- 0.1pX - py + 0.01 pz + 0.001Y, where Own price, Px = $30 Price of a related good, P3, = $3 Quantity demanded = 25.75 Price of a related good, P2 = $275 Consumer income, Y = $20,000 The income elasticity of demand 'g', when equilibrium quantity is 25.75 units and income is $20,000. is equal to :I (enter your response rounded to three decimal places). In this case the good is: O A. an inferior good. 0 B. a normal luxury. 0 C. a normal necessity. O D. an inferior necessity