Which of the following sets are finite or infinite.

$\{1,2,3 \ldots .\}$

Which of the following are sets ? Justify your answer.

A collection of novels written by the writer Munshi Prem Chand.

Examine whether the following statements are true or false :

$\{ x:x$ is an even natural number less than $6\}  \subset \{ x:x$ is a natural mumber which divide $36\} $

List all the elements of the following sers :

$C = \{ x:x$ is an integer ${\rm{; }}{x^2} \le 4\} $

Which set is the subset of all given sets

Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$\{1,2,5\}\subset A$