The correct answer is B) After 24 hours. According to maritime safety regulations, survivors should refrain from consuming any food or water for the first 24 hours after boarding a lifeboat or liferaft. This is to prevent dehydration and other potential complications that can arise from immediate consumption of limited supplies. After the initial 24-hour period, survivors can then begin rationing the available food and water until rescue arrives. The other options are incorrect because: A) 12 hours is too soon to start consuming supplies, C) 48 hours is too long to wait before consuming anything, and D) survivors should not consume any food or water immediately, as this can be detrimental to their survival in the lifeboat or liferaft.