The amount of water recommended by the United Nations for drinking, washing, cooking and maintaining proper hygiene per person per day is a minimum of

Question

$\begin{array}{1 1} (a)\; \text{5 litres } \\ (b)\; \text{15 litres} \\ (c)\;\text{30 litres} \\ (d)\; \text{50 litres} \end{array}$