I would go with E on this one. I solved half this problem with formula and the other half with logically plugging in numbers.
Let A = weight of box A
Let B = weight of box B
Let C = weight of box C
Let T = total weight available in the truck
Let X = total weight of all other boxes in the truck
In this problem, we have to assume that the weight ALREADY in the truck is B + X
From stem 1: A + B > T - (B + X) --> A + B > T - B - X
From stem 2: (T - X) - B > C --> T - B - X > C
Combining both formulas, we get A + B > T - B - X > C
I) says that T - B - X < C which is total opposite of the combined formula. This is false
II) At this point, I plugged in numbers. Say for instance that box B is 25 pounds and box C is 30 pounds, then in order to be able to load box C after removing box B, the available weight left on the truck must be at least 5 pounds; the difference between box B and C. This is true.
III) This says A > abs val (B - C). The combined formula from above is A + B > T - B - X > C which simplifies to A + B > C
A > C - B. This is true
Therefore, II and III are true and E is the answer