Answer:
(A) Consists of a small number of tiny particles that are far apart- relative in their size.
Step-by-step explanation:
An ideal gas is defined as a simplification of a real gas, with punctual particles, in which all collisions are elastic, with random displacements and with no attractive force between them.
The assumption of the particles being punctual make clear that they do not have size at all. So if they were far apart-relative in their size, they can not collide each other, that is why assumption (B) can not be possible (for that particular case).
It is clear that (A) is not an assumption for an ideal gas, because do not fit in any of its properties.
Elastic collision: It is a case in which the energy is conserved (Kinetic Energy).
Kinetic Energy: It is the energy that will have an object as a consequence of its movement.