fU of formation of CH4(g) at certain temperature is -393 kJ mol-1. The value of fH is-

1. Zero

2. <fU

3. >fU

4. Equal to fU

Hint: fH=fU+ngRT
The reaction is 
The formula is as follows:
fH=fU+ngRT
For the given reaction, C(graphite) + 2H2(g)CH4(g)
calculate the value of ng
ng=(np-nr)g=1-2=-1fH=fU+ngRT
 ng=-1fH=fU-2RT
 fH<fU