Can someone help pls! :) btw a primary source is
a first-hand account of an event in history, a source of evidence about an event created by people who experienced the event

Examples diary entries, political speeches, and, government documents

C. A biography of Charlemagne written by his friend and attendant Einhard in the early 9th century.

This is because the attendant would have been living these events as they happened, and because Einhard was a friend of Charlemagne, would have had close and intimate knowledge of how the king behaved in the events as they happened.

a:)

Explanation:

because he originally made it.

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.