One important clue here is the final piece after the underline. "Before doing so" means that whatever action we're describing in the second half has to precede some action mentioned earlier that is performed by the same person. For instance, we might say "You can go swimming, but you should rinse off before doing so," with "doing so" referring back to YOUR action of going swimming. However, we can't say "I will make my pool available for swimming, but you should rinse off before doing so," because the only actual action described before was MINE--making my pool available. There's no action of yours for "doing so" to refer back to.
In this case, the earlier action is "apply for bail." The traffickers are the ones applying, so we need to contrast this with something else the traffickers do before "doing so" [applying for bail]. For that reason, we need D or E, which give the traffickers a second verb ("remain imprisoned") rather than A-C, which attempt to provide a second verb or modifier describing what is DONE TO the traffickers ("imprisoning them").
If we dig into A-C, we might also ask who is even performing these actions. A bill or motion can ALLOW something, but can it IMPRISON someone? It makes more sense for the bill to allow one thing rather than another ("allow them to APPLY rather than REMAIN").
Also, as noted above, we don't want "instead of" for anything but nouns. If we were going to make something like A-C work, it would have to be "to allow . . . rather than to imprison."
(In other news, in a nod to the original poster, RIP Matthew Perry.)