Why do real gases deviate from the ideal gas laws at low temperatures?

The answer is: The volume of a real gas is larger than expected from the ideal gas equation at low temperatures.

An ideal gas is:  

1) made up of molecules which are in constant random motion in straight lines.  

2) all collisions are perfectly elastic, there is no loss of kinetic energy during the collision.  

3) follows ideal gas law: p·V = n·R·T.  

4) the gas particles have negligible volume.  

At low temperatures, volume of the gas is not negligible.

answer; /// i do believe that the correct answer is (c)nuclear bond

i'm pretty sure its b i might be wrong though!