3. (3 points)

(a) In the complete expansion of (m+n+o). (p+g+r+s). (t+w+v+w+z), one obtains

terms such as mpt, nqw, and ort. How many such terms appear in this complete expansion?

(b) Which of the following terms do not appear in the complete expansion from part (a)?

i. mur

ii. nuu

iii. our

iv. ntw

v. pqv

vi. orz