When the A/C System Is First Turned on a Foul

Multiple Choice

When the A/C system is first turned on a foul smell comes out of the duct system.Technician A says that evaporaor icing could be the cause.Technician B says that mold forming in the evaporator case and on the core could be the cause.Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B