Which has maximum number of molecules

Which has maximum number of molecules?
A. 7gm N₂
B. 2gm H₂
C. 16gm NO₂
D. 16gm O₂

[CBSE AIPMT 2002]

In 7gm N₂,
the number of molecules = 7/28 mol
= 0.25 x N_A
In 2gm H₂,
the number of molecules = 2/2 mol
= 1 x N_A
In 16gm NO₂,
the number of molecules = 16/46 mol
= 0.348 x N_A
In 16gm 0₂,
the number of molecules = 16/32 mol
= 0.5 x N_A
Hence, the maximum number of molecules is in 2gm of H₂
So, the correct option is B.