Which of the phrases given below the sentence should replace the phrase printed in bold type to make it grammatically correct? If the sentence is correct as it is, mark 'E' as the answer.

They continued to work in the field despite of the heavy rains.

A.

even though there is heavy rain

B.

although heavily rains

C.

in spite the heavy rains

D.

even though it rained heavily

E.

No correction required

Correct answer is D

No explanation has been provided for this answer.