Answer : The correct option is, (D) Substitution reaction.
Explanation :
Addition reaction : It is a type of reaction in which a molecule combined with the another molecule to give a new larger molecule.
The general representation of this reaction is,

Condensation reaction : It is a type of reaction in which two molecules combine to form a larger molecule and also producing a smaller molecule such as water.

Elimination reaction : It is a type of reaction in which the loss of elements from the starting material to form a double bond in the product.
The general representation of this reaction is,

Substitution reaction : It is a type of reaction in which one functional group is replaced by the another functional group.
The general representation of this reaction is,

(B and C are the two different functional groups)
In the given reaction, Br (functional group) is replaced by the hydroxide ion (functional group). So, this reaction is a substitution reaction.
Hence, the given reaction is a substitution reaction.