Final answer:
The term 'strong' regarding metallic bonds means that a large amount of energy is required to break the bonds; hence, the correct answer is C: a large amount of energy is needed to break the bonds.
Step-by-step explanation:
When referring to metallic bonds, the term 'strong' implies that a large amount of energy is needed to break the bonds between metal atoms in a crystal lattice structure. This is due to the electrostatic attraction between the positively charged metal ions and the delocalized electrons that form this bond. Therefore, the best definition for 'strong' in the context of metallic bonding is option C: a large amount of energy is needed to break the bonds. It is important to distinguish that while metallic bonds provide metals with their characteristic properties, such as malleability and ductility, they are generally weaker than covalent and ionic bonds, with dissociation energies typically ranging from 1 to 3 eV.