The correct answer is C. leisure.
Leisure is time spent away from work, school, or other obligations, devoted to activities that are enjoyable and relaxing. It can include activities such as hobbies, sports, travel, and socializing.
Work is an activity that is done to earn money or to achieve a goal. It can be physical or mental, and it can be done alone or with others.
Boredom is a feeling of being uninterested or restless. It can be caused by a lack of stimulation or by being in a situation that is not enjoyable.
Diversion is something that distracts or amuses someone. It can be a hobby, a game, or a piece of entertainment.
In the given question, Sunil spent most of his time in recreation. This means that he spent most of his time doing activities that were enjoyable and relaxing. These activities could have included hobbies, sports, travel, or socializing.