The Hanging Gardens of Babylon, which stood near a grand palace known as "The Marvel of Mankind", were reputedly constructed by using a combination of baked bricks and of lead coverings, are believed to have been destroyed during an earthquake in the first century A.D.
a) were reputedly constructed by using a combination of baked bricks and of lead coverings, are : Incorrect. 'Combination of X and Y' is the correct idiom. Combination of x and of y is incorrect. There should be 'and' between the two main verbs 'were constructed' and 'are believed'
b) was reputedly constructed by using a combination of baked bricks and of lead coverings and is : Incorrect. Same idiom error as in option a. The main subject is plural, so a plural verb is required.
c) reputedly constructed by using a combination of baked bricks and lead coverings and are : Incorrect. Main verb is missing.
d) reputedly constructed by using a combination of baked bricks and lead coverings and were : Incorrect. Main verb is missing.
e) were reputedly constructed by using a combination of baked bricks and lead coverings and are : Correct. all errors are corrected in this option.