Which is correct and most complete?

a. A design matrix based on

(a) and

(b) in Table 13.19 would be 9 × 4.

b. A design matrix based on

(a) and

(c) in Table 13.19 would be 9 × 4.

c. A design matrix based on

(a) and

(d) in Table 13.19 would be 10 × 6.

d. All of the above are correct.

e. All of the above are correct except

(a) and (d).