Read the sentence below to find out whether there is any grammatical error in it. The error, if any, will be in one part of the sentence. Choose the option with that part as your answer. If there is no error, choose 'D' as your answer. (Ignore the errors of punctuation, if any).
The single biggest gainer in this process was ITC's Gold Flake Kings sales are estimated to have moved up from 50 million to 200 million sticks per month during 1987 and last year.
The single biggest gainer in this process
was ITC's Gold Flake Kings sales are estimated
to have moved up from 50 million to 200 million sticks per month during 1987 and last year.
No error
Correct answer is B
was ITC's Gold Flake Kings sales of which are estimated' or 'whose sales are estimated