Adrian and Kevin Are 24-Year-Old Twins Who Are Both Obese

Multiple Choice

Adrian and Kevin are 24-year-old twins who are both obese. Adrian has been in a committed, long-term relationship for almost two years. Adrian and his girlfriend moved in together a few months ago, and now that they have settled into their new place and new living arrangements, Adrian is looking for a new challenge. So, he decides to start training for a triathlon.
Kevin has recently been putting in a lot of overtime at work (and has sacrificed his social life to do so) , but this extra time is paying off because he's in line for a promotion. He typically spends 10-12 hours a day at the office, six days a week, and will sometimes have dinner with his co-workers, who have become his good friends. Even though Kevin doesn't have much of a life outside of work, he feels like he makes an important contribution and is a valued member of the team.
-As Adrian begins triathlon training and starts exercising more regularly,even though he is eating the same amount as before,he finds that he is often hungrier than he used to be.This is most likely because ___________.

A) the glucose receptors in his brain and liver are signalling that he has low blood sugar
B) his stomach is contracting due to the added exercise
C) his body is releasing less leptin protein now that he is losing weight
D) his body is releasing less ghrelin protein now that his is losing weight