Answer:
is a double displacement reaction (dr).
Step-by-step explanation:
A double displacement reaction (dr) is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.

Combination reaction (C) is defined as the reaction where substances combine in their elemental state to form a single compound.
Single displacement reaction (sr) is defined as the reaction where more reactive element displaces a less reactive element from its chemical reaction.
Decomposition reaction (d) is defined as the reaction where a single substance breaks down into two or more simpler substances.
Combustion (Co) is a type of chemical reaction in which hydrocarbons burn in the presence of oxygen to form carbon dioxide and water along with heat.