Answer:-
Explanations:- The first reaction is combustion reaction as the hydrocarbon is burned in presence of oxygen to give carbon dioxide and water.
Second reaction is the synthesis reaction as in general a synthesis reaction looks like:
Third reaction is the decomposition reaction as it looks opposite of synthesis reaction.
In general, a single displacement reaction looks like:
Fourth reaction is single replacement reaction as bromine is replaced by chlorine.
So, the correct choice is the last reaction, .