Which choice represents a compound?Required to answer. Single choice. (1.5 Points)

Cu

Fe

CO

Br​

CO

Explanation:

Elements will only one capital letter, that may/may not have a lower case letter after it. CO has a capital letter followed by another capital, so it's a compound

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates

the answer is c.the valence of the atoms combine .