Dorm Furnishings manufactures two types of desks. Requirements for each desk are given below.
Standing Desk Executive Desk
Wood panels 5 6
Hardware assembly (hours) 7 6
Staining time (hours) 7 4

The profits for Standing (S) and Executive (E) desk are $1,200 and $1,300, respectively. What is the constraint for staining time?
a. 1,200S + 1,300E
b. 7S + 6E ≤ 42
c. 5S + 6E ≤ 35
d. 75 + 4E ≤ 29