The Sharad Joshi Samman is an award given to recognize achievements in the field of Satire and essay. Satire refers to the use of humor, irony, and exaggeration to criticize and expose the flaws and shortcomings of individuals, institutions, or society as a whole. It is a form of social commentary that aims to provoke thought and bring about positive change. Essays, on the other hand, are written pieces that express the author`s viewpoint and provide a deeper insight into a particular topic.

Option 1, Trade Union activity, is not the correct answer. Trade Union activity refers to the collective actions of workers to protect their rights and improve their working conditions. While this is an important aspect of social activism, it is not the focus of the Sharad Joshi Samman.

Option 2, Social Service, is also not the correct answer. While social service is a noble cause and deserves recognition, it is not specifically the reason for awarding the Sharad Joshi Samman.

Option 4, Cartoon, is not the correct answer either. Although cartoons can be a form of satire, the Sharad Joshi Samman specifically recognizes achievements in the field of satire and essay writing, not cartoons.

Therefore, the correct answer is option 3, Satire