Identify the type of reaction: 2AgCl + BaBr2 -> 2AgBr + BaCl2 A) decomposition
B) combustion
C) double replacement
D) single replacement

C

Explanation:

Just look at the reactants.

2AgCl + BaBr2

The first reactant is made of 2 elements.

The second reactant is made of 2 elements.

It can't be a decomposition. At this level there is only one reactant made of 2 elements. Something like

2MgO ===> 2Mg + O2

is a decomposition.  One compound breaking down into 2 elements Mg and O.

It can't be a combustion. One of the reactants in a combustion is oxygen. Those equations look like

C3H8 + 5O2 ==> 3CO2 + 4H2O

That would be what a combustion looks like

It can't be a single replacement. They look like

Mg + CuO ===> Cu + MgO

There are elements on both sides of the reaction.

that leaves a double replacement which I wrote about how you distinguish it.

i do not get it   at all