If $A$ is any set,then:

Let $U = \{1, 2, 3, 4, 5, 6, 7, 8, 9\}$,$A = \{1, 2, 3, 4\}$,$B = \{2, 4, 6, 8\}$,and $C = \{3, 4, 5, 6\}$. Find $B^{\prime}$.

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{ x : x \text{ is a natural number divisible by } 3 \text{ and } 5 \}$

For each positive real number $\lambda$,let $A_\lambda$ be the set of all natural numbers $n$ such that $|\sin(\sqrt{n+1}) - \sin(\sqrt{n})| < \lambda$. Let $A_\lambda^c$ be the complement of $A_\lambda$ in the set of all natural numbers. Then,

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{ x : x \text{ is a perfect square} \}$

Let $U = \{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 \}$,$A = \{ 1, 2, 5 \}$,and $B = \{ 6, 7 \}$. Then $A \cap B'$ is: