The correct option is D Staying indoors away from metallic doors or windows
During heavy lightning, the whole cloud fills up with electrical charges. A build up of positive charge builds up on the ground beneath the cloud, attracted to the negative charge in bottom of the cloud. The ground's positive charge concentrates around anything that sticks up - trees, windows, metallic doors and a spark of lightning strikes. So, one should stay away from metallic doors or windows as they are also charged.