The correct answer is C. contract writer.
An option writer is a person or entity that sells an option contract. The option writer is obligated to fulfill the terms of the contract if the buyer exercises the option.
An expiry writer is a person or entity that sells an option contract that expires on a certain date. The option writer is not obligated to fulfill the terms of the contract if the buyer exercises the option after the expiration date.
A bond writer is a person or entity that issues a bond. A bond is a debt instrument that represents a loan from an investor to a borrower. The borrower agrees to repay the loan, plus interest, at a specified date.
In conclusion, the correct answer is C. contract writer.