B. Inelastic collision.
In elastic collision , both momentum and kinetic energy are conserved while in inelastic collision only momentum is conserved. there is some loss of energy in inelastic collision during collision.
During the collision of bat with baseball, some energy gets lost to heat and sound. hence the kinetic energy is not conserved although the momentum is conserved.
Answer:



Explanation:
V = Volume of air = 
P = Power = 10 W
t = Time = 1 hour
m = Mass of air = 2 kg
Specific volume is given by

The specific volume at the final state is 
Work done is given by

The energy transfer by work, is 
Change in specific internal energy is given by

The change in specific internal energy of the air is 