Correct Answer : cement
Explanation : A mortar is a mixture of binding material, water, and fine aggregate (such as sand or surkhi). The binding material is typically cement, which is a powder made of a mixture of calcined limestone and clay. When mixed with water, cement forms a paste that hardens over time to bind the aggregate together and create a strong and durable building material. Sand and surkhi are both types of fine aggregate that are often used in mortars, and cinder is a type of coarse aggregate that is not typically used in mortars.
