which example best demonstrates charles’s law?
a.
the volume of a hot air balloon increases as the air inside it is heated.
b.
the pressure inside a pressure cooker increases as the food inside is heated.
c.
a balloon filled with air expands as it rises in altitude.
d.
a syringe pulls in air as the plunger is pulled back.

D.  A syringe pulls in air as the plunger is pulled back.

Explanation:

As per Charles’s law  

At constant pressure for a given amount of a gas,

Volume is directly proportional to its temperature.

Directly proportional means when one increases the other one too will increase. That is when volume increases temperature too will increase. When volume decreases, temperature too will show a decrease.

Option A tells us that the volume of the hot air balloon increase due to the rise(increase) in temperature as the balloon is heated

Thus the expression is

where k is a constant  

When there is a change in the volume and temperature the expression will be

where and are the initial volume and initial temperature and and are the final volume and temperature.