some of the sentence are grammatically correct and some are incorrect. Find which part of the sentence has an error and mark that part. If there is no error,mark that part as your answer
`("He estimated his income tax bill")/a` `("by extrapolation over figures")/b` `("submitted in previous years")/c` `("No error")/d`

Explanation

(b) Use .from. in place of .over.