Answer:
B). Formal.
Step-by-step explanation:
'Formal' learning is described as the learning procedure which involves intentional and purposeful learning from the trained teachers or instructors in an organized and systematic manner.
As per the question, the description provided here exemplifies 'formal' learning as the 'ballet student learns from a trained instructor' who would teach him in a structured way with certain consciously specified objectives. Thus, option B is the correct answer.