I need help with this problem

Answer:
6
Step-by-step explanation:
The number of distinct elements in a finite set is called its cardinal number
Here we are given that the set consists of only the natural numbers and its value lies between 3 and 8 inclusive. Natural numbers are the set of all positive integers, So the set B = {3,4,5,6,7,8}
There are 6 distinct elements so the answer is 6