Select one correct statement . In the gas equation $PV=nRT$

Question

$\begin{array}{1 1} \text{(a) n is the number of mole of a gas} \\ \text{ (b) V denotes volume of one mole of the gas} \\ \text{(c) n moles of the gas have volume V} \\ \text{ (d) P is the pressure of the gas when only one mole of gas is present } \end{array}$