It's a quantitative observation because it includes numerical data.
Answer:

Explanation:
As we know that the sixth order maximum will have path difference given as

here we know that
N = order of maximum

now we have

so we know that


Since the car is at rest, the force experienced by car will be normal face(exerted by surface to which car is in contact) and weight of the car.
As the car is at rest, net force on the car should be zero.
The correct answer is 10 years