Which one of the following environments will sound not travel through?
a. gas
b. solid
c. liquid
d. vacuum

The answer is d. Vacuum

Sound waves need a molecul to travel through. Gas , solid, annd liquid provide that medium.

But vacuum is just an empty space withour any moleculs in it.

Thats why in space, no one can hear you scream. Because it simply not physicsly possible

Edit the post so i can see the letters for each answer, and increase the points required so i'd be able to answer it.