The solution set of $x \equiv 3 \pmod{7}$,where $p \in \mathbb{Z}$,is given by:

Which of the following is a set? Justify your answer.
The collection of ten most talented writers of India.

Are the following pair of sets equal? Give reasons.
$A = \{ x : x \text{ is a letter in the word } \text{FOLLOW} \}$
$B = \{ y : y \text{ is a letter in the word } \text{WOLF} \}$

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

Two dice are thrown. The events $A, B$ and $C$ are as follows:
$A:$ getting an even number on the first die.
$B:$ getting an odd number on the first die.
$C:$ getting the sum of the numbers on the dice $\leq 5$.
Describe the event $A$ or $B$.

Let $A = \{1, 2, \{3, 4\}, 5\}$. Is the statement $\{3, 4\} \in A$ correct or incorrect? Explain.