The volume did not change, it remained at 20 ml
<h3>Further explanation</h3>
Given
20 ml a sample gas at STP(273 K, 1 atm)
T₂=546 K
P₂=2 atm
Required
The volume
Solution
Combined gas Law :

Input the value :

The volume does not change because the pressure and temperature are increased by the same ratio as the initial conditions (to 2x)
A change in temperature is a sign that a chemical reaction has occurred. This occurs in an endothermic reaction. An endothermic process is any process which requires or absorbs energy from its surroundings, usually in the form of heat. It may be a chemical process, such as dissolving ammonium nitrate in water, or simply the melting of ice cubes.
Hopefully im not too late :/
Answer:
I'm so sorry if this is wrong but I think its B