Read each sentence to find out whether there is any grammatical error in it. The error, if any, will be in one part of the sentence, the letter of that part is the answer. If there is no error, then the answer is ( e ). (Ignore the errors of punctuation, if any)
Still remaining in the ancient castle (a)/ are the Duke's collection of early Dutch paintings (b)/ which will be (c)/ donated to a museum. (d)/ No error (e)

Answer

b

Explanation

Use 'is' in place of 'are' as the noun 'collection' is singular.