Which of the following sets is finite or infinite?
The set of months of a year.

From the sets given below,select equal sets:
$A=\{2,4,8,12\}, B=\{1,2,3,4\}, C=\{4,8,12,14\}, D=\{3,1,4,2\}$
$E=\{-1,1\}, F=\{0, a\}, G=\{1,-1\}, H=\{0,1\}$

Which of the following are sets? Justify your answer.
$A$ collection of the most dangerous animals of the world.

Determine the subset for the set $\{n(n+1)(2n+1) : n \in \mathbb{Z}\}$.

Which of the following is an empty set?

Which of the following is a set? Justify your answer.
The collection of all the months of a year beginning with the letter $J$.