Which of the following reactions is a redox reaction? double-replacement acid-base single-replacement

Answer : Option C) Single-replacement reactions.

Explanation : Except combustion reactions where the reductant like fuel and oxidant often is molecular oxygen which reacts vigorously to produce significant amounts of heat, and light, in the form of a flame. This is a kind redox reactions.

But here amongst the given options, single-replacement reactions are redox reactions. As these are the reactions where an ion in solution is usually displaced via the oxidation of a metallic element species. The common example is the acid oxidation of certain metallic element.