Question

in covalent bonds, the atoms that form bonds
a become ions.
b transfer electrons.
c may both be the same element.
d all of the above

Explanation:

In covalent bonds, atoms share electrons instead of transferring them and do not become ions. Atoms of the same element can form covalent bonds, for example, in $O_2$ where two oxygen atoms bond covalently.

Answer:

C. may both be the same element.