Chemical reactions involve changes - changes of reactants into products. Basic chemical reactions can be grouped into categories based on the types of changes that are occuring during the reaction. There are five basic categories - synthesis, decomposition, combustion, single replacement, and double replacement.
 

To be successful with this question, you need to understand the basics of each reaction type. Once understood, you will be able to classify each of the three reactions according to its type. The infographic below describes each of the five reaction types. Study it carefully and then answer the question. You should notice that the process gets easier as you do more questions.