The third one is the answer?
Answer: 21/4 or 5 1/4
Step-by-step explanation: sorry for the 21/4 if this is wroNG IM SOOO SORRy if it is..
Answer:
Step-by-step explanation:

n(D) = 4
Step-by-step explanation:
Given Data:
Set D = {4, 6, 8, 10}
The number of elements in a set is called the cardinal elements (or) cardinality of the sets. This is denoted by n(A).
Here it is denoted by n(D).
The number of elements in the set D is 4.
The cardinality of the set is 4.
Hence, n(D) = 4.