Measure Speed Of Light

Question 1

Is it possible to mesure the speed of light?

Answer 1

Only possibility is to measure a round trip (with a mirror).
Problem with a one way measure is that you would need two clocks, one at the beginning and one at the end, but to synchronize two clocks you need to know the speed of light (because the Synch would be done with a signal going at the speed of light).
In the end we don’t know if maybe on any round trip light at c, or maybe c/2 and 3/2 etc. Einstein made the assumption it is c in both, but he explicitly wrote it was an assumption