PwC concluded that the accounting policy adopted by China Aviation Oil was incorrect because it

only regarded the intrinsic value (i.e. the difference between the strike price and the forward price of the underlying commodity) as the fair value of its options

took into account both the intrinsic value and the time value

only took into account the time value of the option (which includes recognizing the time left to maturity of the option, the volatility of the spot price of the underlying commodity, interest rates and other factors)

used neither the intrinsic value nor the time value