It's generally a bad idea to find questions that don't have official answers posted. Where did you find this question? It's a copyright violation to post questions without citing where you found them!

You post an "Official Solution," but the title says "OA not known." Was B the official answer or not?

Just because the structure "to abandon..., to allocate..., and to sign..." is structurally parallel does NOT mean that this has to be the correct answer. There are often multiple possible parallel structures.

Consider:

I traveled to Japan, visited historic sites, and ate delicious food.
--> all past tense verbs. Ostensibly parallel.

I traveled to Japan, visiting historic sites and eating delicious food.
--> Here, "traveled" is the main verb, and "visiting and eating" is a modifying phrase, giving us more information about what happened while traveling. "Visiting and eating" are parallel to each other, but not to "traveled." THIS IS PERFECTLY ACCEPTABLE! In fact, it arguably makes more sense, since the latter two actions happen while traveling, and are thus not on the same "plane" of meaning as "traveled."

The GMAT wouldn't make you choose between the above two sentences, though. Both are grammatically correct, and both make sense.

In you example sentence, B contains an idiomatic issue: we would say "victims of war crimes," not "victims in war crimes." However, I believe that that idiom issue is minor - "victims in" doesn't ring so false (to my ears, anyway) that it alone would make the answer choice wrong.

I think that this is not a great question, and that B and D are both plausibly correct.

Apologies - I didn't see the previous page and thought you were the original poster.