Final answer:
Approach and stage on the upwind side in flammable gas incidents to avoid the gas blowing towards you and to keep the area free from potential ignition sources.
Step-by-step explanation:
When dealing with flammable gas incidents, it is important to approach and stage on the upwind side (option A). This means that you should approach the scene from the direction the wind is blowing, so that the gas does not blow towards you. Staging on the upwind side also helps to keep the area clear of any potential sources of ignition.