The correct answer is E.
The price of the bench (b) equals its original price (29) minus the discount (4).
Let's see why the other answers are wrong:
Option A suggests to add the discount, instead of subtracting it. So, the discounted bench would cost more than the original one, which clearly makes no sense.
Option B can be rearranged into b = 29+4, which is again option A
Option C can be rearranged into b = 29+4, which is again option A
Option D can be rearranged into b = -29+4, which is the correct option with switched sign
Option E is correct, as already noticed
Option F is not even an equality, so it doesn't make any sense.
