Which rectangle if translated 12 units down and 7 units right will result in rectangle e?
a) rectangle a
b) rectangle b
c) rectangle c
d) rectangle d

The correct answer would be rectangle 'D'.

If we looked at rectangle 'E' and moved it to the left by 7 units (every unit = 1 square on the grid), we would arrive at a point. From then, we can move upwards 12 units and arrive at rectangle 'D'.

Where is the problem

Whose mistake? can you give more details to what the question is asking?