Which of the following are examples of null set?
(i) `A ={"x:x is root of equation x + 3 =0 and "x in N} `
(ii) `B ={x:x in Z,9x -8=0}`
C={x:x is letter of the word MAKE}

Explanation

To determine which of the given sets are examples of a null set, we will analyze each set one by one.

### Step 1: Analyze Set A
Set A is defined as:
\[ A = \{ x : x \text{ is a root of the equation } x + 3 = 0 \text{ and } x \in \mathbb{N} \} \]

1. **Solve the equation**:
\[
...