THEOREM:
Pythagorean theorem:— In a right-angled triangle, the square of the hypotenuse side is equal to the sum of squares of the other two sides.
By pythagorean property,
x² = 10² - 8²x² = 100 - 64x² = 36x = √36x = 6 units.
So, Correct choice - [C] 6 units.