The phrase "to wait on" means to serve someone, especially in the context of hospitality.
So, “to wait on the guest” is the correct and idiomatic expression.
Let’s clarify the other options:
(B) “to wait for the guest” – means to stay until the guest arrives; not the intended meaning.
(C) “to wait the guest” – grammatically incorrect; “wait” is not transitive.
(D) “to await the guest” – formal and grammatically okay, but “wait on” is more natural for the context of serving.