The two true statements are:
a) The molecules in substances A and B are able to move past each other. This is because substances A and B are both in a liquid state, which allows their molecules to move relatively freely and slide past each other.
b) Substance C cannot be compressed into a smaller volume. This is because substance C is in a solid state, which means its molecules are tightly packed together and do not have much room to move. When pressure is applied, the molecules may vibrate more, but they cannot be compressed further.
Therefore, statements c and d are false. All three substances may maintain their own shapes, but this does not mean they will maintain the same shape when their containers are changed. And the volume of substance B will change as pressure increases, as it is a gas and can be compressed.