The Loschmidt number is the number of

Question

$(a)\;\text{molecules present in 1.c.c of a gas at STP} \\ (b)\;\text{molecules in 1 gram mole of a gas at STP} \\(c)\;\text{ atoms present in 1mL of a gas at STP} \\(d)\;\text{ atoms present in 1 gram mole of a gas at STP}$