Which is correct and most complete?

a. With m = 3, f7(x) = x2x3.

b. This model form contains pure quadratic terms.

c. With m = 4, f6(x) = x1 2.

d. With m = 5, f2(x) = 1.

e. All of the above are correct.

f. All of the above are correct except

(a) and (e).