The correct answer is: B. Teacher
A supervised scenario is characterized by the concept of a teacher. In a supervised learning setting, the teacher provides the learner with labeled data, which is data that has been annotated with the correct output. The learner then uses this labeled data to learn a model that can be used to make predictions on new data.
The other options are incorrect because they do not fit the definition of a supervised scenario. A programmer is someone who writes computer programs. An author is someone who writes books or other creative works. A farmer is someone who grows crops or raises livestock.
In a supervised learning setting, the teacher is responsible for providing the learner with labeled data. The learner then uses this labeled data to learn a model that can be used to make predictions on new data. The teacher is not responsible for writing computer programs, books, or creative works, or for growing crops or raising livestock.