Please help I’ll mark as brainliest if correct!

Click on the implied main idea of each selection.

A. Throughout history, people have found better and better ways to measure the passing of time.
B. The hourglass is a slightly more recent invention than the sundial.
C. The first methods of measuring the passing of time took advantage of the changing shadows cast by the sun throughout
D. A primitive clock invented in about 1300 was the most exact way to tell up to that point.