It would be C i’m pretty sure
I need the options to choose from

An element is a substance that can't be broken down further. Lithium (Li) and calcium (Ca) are examples of elements.
Carbon monoxide (CO) and potassium bromide (KBr) are examples of compounds, which are made up of more than one element put together.
Comets are usually formed of ice and other suave debris, while asteroids typically contain metals.
The correct answer is B. Platinum is the transition element among the choices. The elements belonging to this group are those having a partially filled d or f subshell. It usually refers to the d-block transition elements of the periodic table.