The correct choice is (a) Puldo
The best explanation: When Compound like Pludo, impermo, etc. Are added to cement during construction, it prevents seepage, leakage and damp cause by capillary absorption of the moisture in cement, mortar and concrete. The quantity of water proofing compound to be added is also very small, set 2% and does a bag of cement will require only about 10 N of such compounds.