Hi Arun,

The first time that Larry walked down the ramp, laden with packages, he tripped and nearly dislocated his shoulder.

It is clear that you get the intended meaning of the sentence. You agree that “laden with packages” should modify “Larry”.

According to GMAT, the verb-ed modifier is a noun modifier that should be placed to the entity it modifies as close as possible. Generally, verb-ed modifiers modify the immediate preceding noun or noun phrase.

In this sentence, “laden” is a verb-ed modifier which is places next to ramp. Even if it separated from “ramp” by comma, “ramp” is the immediate preceding noun and per the GMAT, “laden” will modify “ramp”. But this is certainly not the intended meaning of the sentence. Hence, we must put “laden” close to Larry so that there is no modification error.

You can also read this post for the correct usage of verb-ed modifiers:
verb-ed-modifiers-vs-verb-ing-modifiers-125611.html?fl=similar

I do agree that in Choice D, we need a comma after “ramp”. However, placement of comma alone has never been the deterministic issue for eliminating an answer choice. GMAT exclusively does not test the correct placement of punctuations. Moreover, to avoid a punctuation error, which is not even an error per GMAT, we are committing a graver error of modification by choosing A. Now modifiers are certainly deterministic errors to eliminate an answer choice.
Hence, we must choose the most ideal answer choice and that is choice D.

Hope this helps.
Thanks.
Shraddha