I'm not quite sure which of these semantic relationships it would be: Synonymy, Hyponymy, Hypernymy, and Antonymy. Or would there be no semantic relationship between these words?
The way they are presented here, you assume they are antonyms in a given context, but you are aware that's not always true. Strictly speaking, you cannot take primary verbs (as opposed to verbs derived from nouns) out of context and assign them tense, aspect, semantic relation, just as you cannot take man and assign a unique Position of Sentence (PoS) without corresponding sentence.
Proof: I would always prefer answer or respond, being a second language learner though, and I tend to understand tell as a synonym of say (or at least a close hyponym, as ?say me is not synonym, but say! is). But that's off-topic here, because it depends on language specific context. The proof will be complete once the question is closed. And my answer can't be denied by being accepted. This is proof by contradiction. Q.e.d.