During 3rd day to 2nd week of starvation, brain depends on which of the following substance as fuel:

For brain, Glucose is the main/preferred fuel during Fed as well Fasting state whereas during Starvation, Brain depends upon Ketone Bodies as the fuel. So, answer is A - Ketone bodies. ADDITIONAL EDGE: Fed state: When we eat food (Within 2 hours of food intake is called Fed state) Fasting state: In between meals, when we are not eating food (From 12-18 hours after food upto 48 hours is Fasting) Starvation: Severe or complete lack of nutrients (since last 1-3 days) In between meals and night time is called Fasting time. That's why Breakfast is named -->BREAK THE NIGHT FAST.