Oh this is great. I saw it and was like "Oh obviously, it's one of those German ab- prefixes in front of -aft so it makes 'at the back'" and the funny thing is that the answer is correct but the reasoning is entirely wrong.
Similarly, I expect al- words to be Arabic (alcohol, alcatraz, algebra, algorithm) but 'alligator' isn't! And 'admiral' is!
Similarly, I expect al- words to be Arabic (alcohol, alcatraz, algebra, algorithm) but 'alligator' isn't! And 'admiral' is!