Sentence Correction

By installing special electric pumps, farmers' houses could be heated by the warmth from cows' milk, according to one agricultural engineer.

(A) farmers' houses could be heated by the warmth from cows' milk, according to one agricultural engineer
(B) the warmth from cows' milk could be used by farmers to heat their houses, according to one agricultural engineer
(C) one agricultural engineer reports that farmers could use the warmth from cows' milk to heat their houses
(D) farmers, according to one agricultural engineer, could use the warmth from cows' milk to heat their houses
(E) one agricultural engineer reports that farmers' houses could be heated by the warmth from cows' milk


please let me know the choice as i find it bit tricky

ruplun wrote:By installing special electric pumps, farmers' houses could be heated by the warmth from cows' milk, according to one agricultural engineer.

(A) farmers' houses could be heated by the warmth from cows' milk, according to one agricultural engineer
(B) the warmth from cows' milk could be used by farmers to heat their houses, according to one agricultural engineer
(C) one agricultural engineer reports that farmers could use the warmth from cows' milk to heat their houses
(D) farmers, according to one agricultural engineer, could use the warmth from cows' milk to heat their houses
(E) one agricultural engineer reports that farmers' houses could be heated by the warmth from cows' milk


please let me know the choice as i find it bit tricky

Well I needed like 10 seconds to answer this one because who is installing the pump --> the farmer. So D is the only possible choice. All other questions have modifier problems.
After a second look I saw that C is also a possible answer, but you see in the original sentence that the engineer reports. Furthermore you see that you don't really need the last part of the original sentence "according to one agricultural engineer". So the farmer has to install the electrical pumps.

IMO D:

By installing special electric pumps : should modify to farmers.
So only D makes sense.

thanks