Question

B is the set of natural numbers less than 9

Answer 1

the set of natural numbers is {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, ...}

basically it's the set of positive whole numbers

Answer 2

if you only focus on the numbers less than 9, you get this

{1, 2, 3, 4, 5, 6, 7, 8}