PLEASE ANSWER ASAP WILL MARK BRAINLIEST!!! Which of the following most likely explains why the chemical symbol for calcium is Ca?

a.) The symbol C was already used for carbon.

b.) The symbol was assigned by modern alchemists.

c.) Calcium is made of more than one type of atom.

d.) The element is named after the Latin word for calcium.

Johnny rode his bike 4 blicks down the street to his friend's house once he got to his friend house and realized he could not cone out to play he turned aroubd and went back home.what is displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point