PLEASE HELP! Simplify radical square root -100

Answer: OPTION 3 10i
Step-by-step explanation:
First of all, you need to know about imaginary number, or i.
i (imaginary number)= √-1
---------------------------------------------------------
√-100=√100 × √-1 ⇔ This splitting up √-100 to make it easier for you to understand.
√-1=i ⇔ As mentioned before of the concept of imaginary number
√100= 10 ⇔ It is a perfect square
√-100=√100 × √-1
√-100=10 × i
√-100=10i
Hope this helps!! :)
Please let me know if you have any question