Answer:
The simplest radical form is
⇒ (c)
Explanation:
To simplify any square root;
- Factorize the number under the root using prime numbers
- Take out the root any number repeated twice as one number
Examples:
1. Simplify

factorize 8 using prime numbers
8 = 2 × 2 × 2, then

Take two of 2 out the root, then

2. Simplify

factorize 18 using prime numbers
18 = 2 × 3 × 3, then

Take the two 3 out the root, then

Let us simplify

∵ 45 = 3 × 3 × 5
∴

→ Take the two 3 out by one 3
∴

→ Multiply the numbers out the root
∴

∴ The simplest radical form is
