Answer: Option (D) is the correct answer.
Step-by-step explanation:
According to the octet rule, in order to attain stability every atom requires to complete its octet by gaining or losing valence electrons.
The reactivity of an atom depends on the number of valence electrons. Smaller is the number of valence electrons to be gained or lose, the greater will be the activity of atom.
For example, atomic number of chlorine is 17 so, it just needs to gain one more electron to completely fill its shell. Whereas atomic number of aluminium is 13 so, it needs to lose 3 electrons in order to gain stability.
Thus, activity of chlorine atom will be more as compared to aluminium atom.
Thus, we can conclude that smaller the number of electrons an atom has to borrow or to lend, the greater the activity of the atom.