The equation $X(1 + r)^{-t} = S + c - p$ is inconsistent with the put-call parity equation. The put-call parity equation is given by $c + X(1 + r)^{-t} = S + p$, where 'c' is the call price, 'p' is the put price, $X(1 + r)^{-t}$ is the present value of a zero-coupon bond, and 'S' is the current price of the stock. Rearranging this equation, we get $c = S + p - X(1 + r)^{-t}$, which is the price of a call option. The equation in choice C rearranges the terms in a way that does not represent any of the individual securities in the put-call parity relationship, making it inconsistent with the put-call parity equation.

Choice A is correct in representing put-call parity. It states that the price of the underlying asset (S) is equal to the price of a call option (c) minus the price of a put option (p), plus the present value of strike price $X(1+r)^{-t}$.

Choice B is correct in representing put-call parity. It states that the price of a put option (p) equals call option's price (c) minus underlying asset's current market value (S), plus present value of strike price $X(1+r)^{-t}$.

Choice D is correct in representing put-call parity. It states that call option's cost (c) equals current market value (S) plus cost of protective put (p), minus present discounted value of exercise or strike price $X(1+r)^{-t}$.