The correct answer is A. time of expiry increases.
The option price is the amount of money that an option buyer pays to the option seller in exchange for the right, but not the obligation, to buy or sell an underlying asset at a specified price on or before a specified date. The option price is determined by a number of factors, including the strike price, the time to expiration, the volatility of the underlying asset, and the interest rate.
As the time to expiration increases, the option price increases. This is because the buyer of the option has more time to exercise the option, which gives them a greater chance of making a profit.
The other options are incorrect because they do not affect the option price. The exchange time is the time it takes to complete a trade on an exchange. It does not affect the option price because the option price is determined at the time the option is purchased.