List all the elements of the following set:
$F = \{ x : x \text{ is a consonant in the English alphabet which precedes } k \}$

Consider the experiment of rolling a die. Let $A$ be the event 'getting a prime number' and $B$ be the event 'getting an odd number'. Write the sets representing the events $A$ and $B$.

Write down all the subsets of the following set: $\{a, b\}$

Which of the following are sets? Justify your answer.
The collection of all natural numbers less than $100$.

Write the set $A = \{ 1, 4, 9, 16, 25, \dots \}$ in set-builder form.

Let $A, B$ and $C$ be three sets. If $A \in B$ and $B \subset C$,is it true that $A \subset C$? If not,give an example.