Guys, I initially chose D, but now I realise that we need "old english" as the subject of the sentence. It is "old english" that was "very difficult", not "genders". So, it looks like we need to choose between A and B.
I have 2 issues with A and B:
1. How "Old English had three genders" can be parallel to "those of the Germans"?
2. Grammatically A and B are exactly the same - "that resembled" and "resembling" mean the same thing. So, how would you choose between the two?
On the test day, however, I would choose B only because "resembling" takes the tense of the main clause(simple past); even if "had" and "that resembled" in A are both in the simple past tense, I think, specifying the tense of "resemble" leaves doubt that the two events ( having and resembling) started and finished at not exactly the same time.
vscid
Old English had three genders that resembled those of the Germans and so was probably very difficult for a foreign traveler to learn in a short time.
a] Old English had three genders that resembled those of the Germans
b] Old English had three genders resembling those of the Germans
c] The three genders of Old English resembled a German's
d] Old English's three genders resembled the German's
e] The three genders of old English that resembled those of the Germans