What does "a ∩ b = b" imply about the objects a and b?

When interpreting the expression "a ∩ b = b," it signifies the relationship between two sets or features, a and b. The intersection of the two sets, denoted by "a ∩ b," is the set of all elements that are common to both a and b. Therefore, if the intersection equals b, it means that all elements of b are also found in a.

This implies that feature b is entirely contained within feature a. In a spatial context, you can visualize this as feature b being completely within the boundaries of feature a. As a result, this relationship confirms that every part of b is included in a, reinforcing the idea that the entirety of b lies within the confines of a.

This reasoning effectively supports the conclusion that the correct answer is that feature b is within a.