The electrons present in the _________ of an atom are known as the valence electrons.

Correct option is A

The correct answer is (a) Outermost shell.
· Valence electrons are those electrons that reside in the outermost shell of an atom in its electron configuration. These electrons play a crucial role in chemical reactions and bonding because they can be gained, lost, or shared in chemical reactions.
· The properties of elements, particularly their chemical reactivity and the types of bonds they can form, are largely determined by the arrangement and number of their valence electrons.