When maximizing 4x + 8y subject to 5x + 3y ≤ 30, x ≥ 0, y ≥ 0, what are the corners of the feasible region?
Select one:
a. (6,0); (0,10); (0,0)
b. (3,0); (0,3); (0,0)
c. (6,1); (1,10); (0,0)
d. (6,6); (10,10); (0,0)

Question 2:
When minimizing x - y subject to x+y≤ 4, x>0, y ≥ 0, what are the corners of the feasible region?
Select one:
a. (4, 0); (0, 4); (0, 0)
b. (5, 0); (0, 5); (0, 0)
c. (4,1); (1, 4); (0, 0)
d. (-4, 0); (0, -4); (0, 0)

Question 3:
When minimizing 4x+8y subject to 5x + 3y ≤ 30, x ≥ 0, y ≥ 0, what is the minimal value that the objective function reaches?
Select one:
a. 20
b. -10
c. 80
d. 0