what does it mean for a set to be close

Question

a.) members of the clothes that cannot be added, subtracted, multiplied, or divided
b.) the set has a infinite number of members as opposed to being infinitely large
c.) an expression belonging to a set cannot be used to create an expression that is not the set
d.) an operation performed on members of will result in a member of the same set

Answer 1

The correct option that describes what it means for a set to be "closed" is:

d.) an operation performed on members of the set will result in a member of the same set.

In mathematical terms, a set is said to be closed under a particular operation (such as addition, subtraction, multiplication, or division) if performing that operation on any elements of the set always yields an element that is also in the set. For example, the set of integers is closed under addition because the sum of any two integers is also an integer.