If a solid metal reacts with a metal in solution, that means the solid metal has displaced the metal in solution. Therefore the solid metal was more reactive than the metal in solution. Keeping this in mind, look at which metals reacted:

(Let (s) denote a solid metal and (aq) denote a metal in solution)

3 (s) with 1 (aq), 2 (aq), 4 (aq).

1 (s) with 2 (aq), 4 (aq).

2 (s) with 4 (aq).

4 (s) with nothing.

Just from this alone we can deduce the order to be 3 -> 1 -> 2 -> 4 from the number of reactions of each solid metal, but we can go a bit more in depth:

We see that 3 (s) has reacted with all the aqueous solutions (most reactive), and 4 (s) with none of them (least reactive).

That means the order is 3 -> ? -> ? -> 4.

Then note that 1 (s) reacted with 2 (aq). So 1 -> 2.

Therefore the order is 3 -> 1 -> 2 -> 4.