Amajor difference between the "gas giants" and the "ice giants" is that
select one:
a. only the gas giants contain a layer of liquid metallic hydrogen in their interiors
b. only the ice giants produce vortex storms in their atmospheres
c. only gas giants will become stars later in their lifetimes
d. only gas giants have satellites

Option (A)

Explanation:

Gas giants and ice giants are collectively known as the Jovian planets. The gas giants are Jupiter and Saturn whereas the ice giants are Uranus and Neptune. They are called ice giants because they are far away from the sun and the temperature in that region is very cold.

They are both comprised of the atmospheric gases namely hydrogen and helium along with the presence of some other gases such as ammonia and methane. But ice giants and gas giants differ from one another by the presence of a layer that contains the liquid metallic-hydrogen layer in the interior of gas giants. It is absent in the ice giants. This metallic hydrogen layer is quite big in Jupiter than in Saturn, which could be due to the bigger size of Jupiter.

This layer of liquid hydrogen has formed due to the extremely increasing pressure and temperature condition that converts  

the gaseous hydrogen into a liquid form.

Thus, the correct answer is option (A).