Vader's and ObiWan's light Saber - Option B
Vader's lightsaber is red, while Obi-Wan's lightsaber is blue, meaning that Obi-Wan's lightsaber is emitting higher energy light waves compared to Vader's lightsaber.
When the flame is very high which indicates that when it is in its highest peak. When it is in its highest peak it is blue. Consider if we on a stove then we observe that flame is blue inside because it is in hottest state so therefore higher energy light waves.