Specialisation in MBA would depend on your friend's interest and what type of job has he handled in Pizza Hut. If he is good at numbers then Finance is better. However, if he is interested in Ops then MBA (Ops) is better. If he has handled sales then Marketing is better.
Secondly, it is not a question just attaining some degree. Your friend should make his complete career plan for the next 5-10 years and MBA degree should be means to achieve his career goal. MBA itself cannot be career's goal.
Lastly, why your friend has not raised query on this forum about his career?
All the best to your friend.
30th August 2015 From India, Bangalore