The characteristics of two different types of reactions are shown below: Reaction A: Protons are gained or lost by the atom of an element.
Reaction B: Electrons are lost by the atoms of an element.

Which statement is true about the two reactions?
- Valence electrons are not involved in both Reaction A and Reaction B.
- Valence electrons are involved in Reaction B but not in Reaction A.
- Valence electrons are involved in both Reaction A and Reaction B.
- Valence electrons are involved in Reaction A but not in Reaction B.