Standard rainbow option payoffs are based on either the maximum or minimum of the underlying asset set.

• A is a standard rainbow call payoff: $\max(0, \max(S,Q,C)-K)$.
• B is equivalent to A, since $\max(S,Q,C,K)-K = \max(0,\max(S,Q,C)-K)$.
• C is a standard rainbow put payoff: $\max(0, K-\min(S,Q,C))$.
• D is not a standard rainbow payoff, because $K-\max(S,Q,C,K)$ is not the usual nonnegative option payoff structure based on the minimum asset.

Thus, the exception is D.