6. Which of the following statements must be true given a two good economy? I. Hicksian demand function is homogenous of degree 0 in px and py. II. Marshallian demand function is homogenous of degree 0 in px, py, and I. III. The Marshallian demand function is less negatively sloped than the Hicksian demand function for a normal good.

(a) I and III (b) I and II (correct) (c) II and III (d) I, II, and III

My question is why is the Hicksian demand function is homogenous of degree 0 in px and py?