If x = √125 × √30 ×√6, then x is equal to:

Correct option is A

First, break each term under the square root into prime factors or simpler radical forms:
1. $$\sqrt{125} = \sqrt{25 \times 5} = 5\sqrt{5}.$$​
2. $$\sqrt{30} = \sqrt{5 \times 6} = \sqrt{5} \times \sqrt{6}.$$​
3.$$\sqrt{6} is \sqrt{6}​.$$​
So,
$$\sqrt{125} \times \sqrt{30} = (5\sqrt{5}) \times (\sqrt{5}\,\sqrt{6})$$$$= 5 \times(\sqrt{5} \times \sqrt{5}) \times \sqrt{6} = 5 \times 5 \times \sqrt{6} = 25\sqrt{6}​.$$​
Multiply by \sqrt{6}​:
$$25\sqrt{6} \times \sqrt{6} = 25 \times 6$$​ = 150.