Classify the following into empty sets or singleton sets.
(i) A = {x :x is a composite number which is having less than three factors}
(ii) `B = {x : x in R, x" is a multiplicative inverse of "2016}`
(iii) `C={x : x in N, x" is neither prime number nor composite number"}`

Explanation

(a) Every composite number has at least three factors. There is no composite number having less than three factors.
`:. A` is an empty set.
(b) The multiplicative inverse of 2016 is `1/2016`.
`B={1/2016}`
`:. B` is a singleton set.
(c) In a set of natural numbers, 1 is neither prime nor composite.
`C={1}`
`:. C` is a singleton set.