A is correct - it's basically a repackaging of the assumption that particles are point masses (i.e. have no volume/infinitely small volumes)
C is correct - it, again, is a repackaging of the assumption that particles do not interact with each other.
E is correct - pressure experienced is a result of the gas particles bouncing off the walls elastically.
B is wrong because straight-line is ambiguous (i.e. along only one axis or circular/accelerated motion?). Either way, it generally has nothing to do with kinetic theory.
D is wrong - all the collisions are ELASTIC. You probably just remembered wrong.
F is wrong - it's not proportional to celsius temperature but to absolute temperature, i.e. the Kelvin Scale.
Hope that helps!