If we put an incense stick on top of an open beaker, in which a candle is burning in centre, which way will the flame go?

a) The smoke is pulled inside the beaker when the incense stick is kept at the mouth of the beaker.
b) The smoke moves upward when the incense stick is kept above the flame because hot air from the flame rises upwards.
c) The smoke flows towards the bottom of the flame when the stick is kept at the edge as air is required for combustion of wax.