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, the answer is 'E'. (Ignore the errors of punctuation, if any).
He has a scheme of his own which he thinks more preferable to that of any other person.
He has a scheme
of his own which he thinks
more preferable to
that of any other person.
No error
Correct answer is C
preferable to