Concept:The strength of a metallic bond depends on how many valence electrons each atom releases into the delocalised electron sea.
Explanation:In metallic bonding, metal atoms lose their valence electrons to form positive ions surrounded by a sea of mobile electrons.
When a metal has more valence electrons per atom, the positive charge on the cations is higher.
This creates a stronger electrostatic attraction between the cations and the delocalised electrons.
Therefore, the metallic bond becomes stronger with an increase in the number of valence electrons.
It is not determined by ductility or the total number of electrons in the atom.
Answer:C. number of valence electrons