I do believe the early Egyptians, being as smart as they where used a interesting method of a sundial. It caught the suns shadow and they where able to use it to tell the time.
Atlanta is 3 hours ahead of Seatle. (USA Eastern Time)
So, If I live in Atlanta and my grandparents love in Seattle, and they want to call me before 10 pm, I should expect their call around 7 pm in Seatle
The answer that you are looking for is A) He had experience