Is "quickly processed" correct?

[mbadreams]

OG 11 Q.65
Q. The only way for growers to salvage frozen citrus is to process them quickly into juice concentrate before they rot when warmer weather returns.

A.
B. if they are quickly processed into juice concentrate before warmer weather returns to rot them
C. for them to be processed quickly into juice concentrate before the fruit rots when warmer weather returns.
D. if the fruit is quickly processed into juice concentrate before they rot when warmer weather returns.
E. to have it quickly processed into juice concentrate before warmer weather returns and rots the fruit.

The Ans is E. But is it right when "quickly" is placed before the past participle "processed". Can someone please explain why it isnt "to have it processed quickly"

[capnx]

ofcourse. if the participle is used as a modifier, the only thing that can modify a modifier (either adj or adv) is an adverb. quickly is adv, and it can come before or after the word it modifies
The meaning is slightly different though

To process it quickly: the process itself is quick
To quickly process it: to begin the process quickly or to run the process quickly.

ie:
He spoke quickly: the speed he spoke is quick
He quickly spoke: the speed in which he started speaking was quick