Question

Fill in the blank with the most appropriate word.
I'm not absolutely certain ______ it.

• A. with
• B. of
• C. by
• D. in

Answer 1

The correct option is B of

Option B is the correct answer because 'of' is used to mean relating to something.

Options A, C and D are incorrect because 'with' is used to indicate possession, 'by' is used to indicate proximity or agency and 'in' is used to refer to an unspecific location or time.