YUP THATS CORRECT
I ALSO MARKED IT
BUT ANS GIVEN IS WRONG..
the VW's constant 'a' for CO2 gas is greater then that of H2 gas.
it means dat :
a) strength of VW force of CO2 gas < that of H2
b) -------------------------------------------- = ----------------
c) CO2 gas can be more easily liquified
d) H2 gas can be more easilly liquified..