Kiernan (the contractor) is to build eight homes on a block in a new subdivision, using two different models: standard and deluxe. (All standard homes are the same, and all deluxe models are the same.)

(a) How many different choices does Kiernan have in positioning the eight houses if they decide to build three standard and five deluxe models?

A. 56
B. 84
C. 112
D. 168

(b) If Kiernan builds four deluxes and four standards, how many different positionings can they use?

A. 70
B. 140
C. 210
D. 280