The observational fact about a cepheid variable star that leads to a measurement of its distance from earth is that its period of variation is directly related to its

absolute brightness

Explanation:

The observational fact about a cepheid variable star that leads to a measurement of its distance from earth is that its period of variation is directly related to its absolute brightness

"the location of the epicenter" would be the correct answer

answer(c) carved on a babylonian clay tablet that showed earth as a flat circular disk;