Answer:
B. equatorial
Step-by-step explanation:
The equatorial coordinate system is a universal system that can be used by anyone in the world. Because it is adopted in all countries, two people in different countries who want to observe the same meteor shower and talk about it, must use the equaltorial coordinate system to be able to observe the same point in space.
This is possible because there is only one equatorial plane on the planet, which allows the creation of universal coordinates that assume an equal value regardless of the region of the planet where they are measured.