Metal A displaces metal B from an aqueous solution of its salt, and metal B displaces metal C from an aqueous solution of its salt. Which metal is the most reactive?

Correct answer: Metal A

In a displacement reaction, a more reactive metal displaces a less reactive metal from its salt solution. Since A displaces B, A is more reactive than B. Similarly, B is more reactive than C. Thus, the reactivity order is A > B > C, so metal A is the most reactive. Option B is more reactive than C, but it is less reactive than A.