Hmm, I don't have my text books to hand, but I'd have said would seem to be LONGER and your approach could be too LOW.
For the high/low question, draw a side-view of the situation. Draw an up-sloping runway, with an aircraft in the correct position on final approach. Then, holding the runway threshold still, rotate the page so that the runway "appears" flat - this is simulating what your brain sees. Notice that the aircraft moves up - in other words, your brain thinks you are too high (when you're not), and so you fly down, causing you to be too low.
The apparent length of the runway can also be answered with this rotating-page technique. Think about the road-markings that you see painted on the road - they are very long when viewed from above, but from your car they look normal. The flatter the viewing angle, the shorter the image appears. But an up-sloping runway gives you a less-flat viewing angle, so the runway appears longer.
I think.
FFF
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Edit, because the more I think about it, the more I think I'm wrong, and B) is the correct answer. Except I can't explain it.... will come back later once I've thought about it more, unless someone else explains it well first.