Answer:
In the given situation, the professor is promoting the disengagement theory.
Explanation:
The disengagement theory was the first theory of aging, stated in a book named Growing Old. According to this theory, aging is an inevitable and a natural process, which results in reduced interactions of the aging person with the society. It also states that the aging people tend to withdraw from personal as well as social relationships.
Therefore, the professor is promoting the disengagement theory.