Answer : The correct option is, (a) Synthesis
Explanation :
Synthesis reaction : A chemical reaction where multiple substances or reactants combine to form a single product.
It is represented as,
\(X+Y\rightarrow XY\)
Combustion reaction : A chemical reaction in which a hydrocarbon react with the oxygen to give product as carbon dioxide and water.
It is represented as,
\(CH_4+2O_2\rightarrow CO_2+2H_2O\)
Single replacement reaction : A chemical reaction in which the more reactive element replace the less reactive element.
It is represented as,
\(A+BC\rightarrow AC+B\)
In this reaction, A is more reactive element and B is less reactive element.
Double replacement reaction : It is a type of chemical reaction where a positive cation and a negative anion of two reactants exchange places to form two new products.
It is represented as,
\(XY+AB\rightarrow XB+AY\)
(X and A are the cations, Y and B are the anions)
The given reaction is, \(Ca+Cl_2\rightarrow CaCl_2\)
In this reaction, calcium combine with the chloride to form calcium chloride as a product.
Hence, the given type of reaction is a synthesis reaction.