Answer:
The radius of the disc is 2.098 m.
(e) is correct option.
Explanation:
Given that,
Moment of inertia I = 12100 kg-m²
Mass of disc m = 5500 kg
Moment of inertia :
The moment of inertia is equal to the product of the mass and square of the radius.
The moment of inertia of the disc is given by

Where, m = mass of disc
r = radius of the disc
Put the value into the formula



Hence, The radius of the disc is 2.098 m.
Definitely D. The brakes on a bike rub against the wheel. Not sure about the others.
The answer is a.12.5kg because i just did the test and it was correct.
hope this helps