What is the most cost-effective way to accurately measure the height of a ceiling when ladder use is not allowed?

What is the most cost-effective way to accurately measure the height of a ceiling when ladder use is not allowed?
A . Estimate the height based on known object sizes
B . Gather measurements from other objects and do the math
C . Rent a lift-cart to lift you up to the ceiling
D . Use a laser measure to measure the distance from the floor to the ceiling

Answer: D