Although it might be true that the chemical identity of Cl (Chlorines) is known to be highly reactive, but when it combines with another element, it loses its former chemical identity. This means that Cl and NaCl would definitely have different chemical identities and therefore different reactivities. Another great example would be O (Oxygen). It is a gas in its natural state when alone but then it becomes a liquid when combined with H (Hydrogen) to form what we called water (H2O). Therefore the correct answer among the choices would be:
Cl is highly reactive you would expect NaCl “To have completely different properties”.