Riddle

Though easy to spot, when allowed to plume, it is hard to see, when held in a room.

Choose an answer

A.Steam
B.Fog
C.Dust
D.Smoke
Hint: It's a word with 5 letters, starting with "S".

Answer

Smoke

Why this is the answer

Smoke billowing outside is easy to spot, but when trapped and thinned in a small room it becomes harder to visually pick out in the air.

This riddle is filed under Hard/Difficult Riddles and rated Medium.