Examine whether the following statements are true or false :

$\{a\} \subset\{a, b, c\}$

Which of the following sets are finite or infinite.

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

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.

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

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

If a set $A$ has $n$ elements, then the total number of subsets of $A$ is