Define the variable for the hours of the post office and describe a constraint for the following situation. Susan needs to mail a package. The only day she can go to the post office is Saturday. The post office is open from 9 : 00 a.m. to 12 : 00 p.m. on Saturdays. h = hours of the post office; 9 ≤ h ≤ 12 h = hours of the post office; 8 ≤ h ≤ 9 h = hours of the post office; 12 ≤ h ≤ 9 h = hours of the post office; 3 ≤ h ≤ 6.