Valence Electrons are? choose the correct answer

a. The number of electrons are lost
b. The number of electrons gained
c. Electrons in the highest occupied energy level of an atom
d. Electrons in the lowest energy level of an atom

I would say "c".

They are the electrons that are located in the shell with the highest principal quantum number, i.e. highest energy level, therefore they are available to be either lost, gained, or shared to form stable (i.e. lower enery) compounds.

Valence electrons are the electrons, that take part in the formation of a chemical bond. Valence electrons are on the outermost shell, so my answer is c) Electrons in the highest occupied energy level of an atom.
but I'm not sure.

@Mia
"The n = 1 orbital has the lowest possible energy in the atom. Each successively higher value of n has a higher level of energy"

d.
valence electrons are the no. of electros present in the outermost shell of an atom that is its lowest energy level .Since the outermost electrons experience less attractive force of nucleus , they are capable of gaining or losing to form ions.

The answer is C