The first time that Larry walked down the ramp, laden with packages, he tripped and nearly dislocated his shoulder.
(A) Larry walked down the ramp, laden with packages,
(B) Larry walked, laden with packages, down the ramp
(C) Larry walked down the ramp, with laden packages,
(D) Larry, laden with packages, walked down the ramp
(E) Larry, laden with packages, had walked down the ramp,
Yes, D is correct. The comma at the end of (D) is not necessary--even if you are not sure about that, you should still guess (D). The GMAT usually does not test you on whether there should be a comma in a specific place. Sometimes they do--but usually there are other things more important to which you should pay attention..
Remember you do not want to alter the meaning of the original statement which states two things:
1) Larry walked down the ramp
2) Larry was laden with packages
(D) and (E) keep this meaning, but (E) complicates it further with a "past-past" tense phrase "had walked"...there is no change in timing so no change in tense needed..(D)
When would you use "had walked" some of you might ask? Well, if the sentence said something like "When Larry walked down the ramp, he remembered he had tripped at this same spot 5 years ago"....
Here with the word "remembered"--it suggests a transition to the past...therefore you use the "past-past tense"..
But with this question "The first time"--does not do the same and so does not require "past-past" tense.
