Answer:

D. universal set

Explanation:

hope it helps

Answer:

D. Universal Set

Explanation:

For any set problem or discussion, a universal set (U) is a "larger" set that contains all of the elements that may be of interest in the discussion; in particular, the universal set at least contains all of the elements of all of the sets in the discussion.

Info: https://www.math.fsu.edu/~wooland/hm2ed/Part1Module1/Part1Module1.html#:~:text=For%20any%20set%20problem%20or,the%20sets%20in%20the%20discussion.&text=This%20set%20is%20called%20the%20complement%20of%20S%2C%20and%20is%20denoted%20.