A: Call-put parity can also be called "rise-fall parity", which refers to a parity relationship between European call options and corresponding European put options. Specifically, the mathematical expression of this parity relationship is: Vc+Xe-rft=Vp+S, where Vc represents the value of European call option; X represents the exercise price); The right to choose; Rf stands for risk-free interest rate; T represents the remaining validity of the option; Vp represents the value of European put options; S represents the initial price of the underlying asset.