Yttrium and Niobium have only 1 stable isotope each. However, elements adjacent to them in the same row such as zirconium and molybdenum have multiple stable isotopes. Identify the statement that explain this phenomenon.

• A. Having even number of neutrons lower the nuclear binding energy, making odd nuclei generally less stable
• B. Heavier elements generally have lower number of stable isotopes.
• C. Having odd number of protons lower the nuclear binding energy, making odd nuclei generally less stable
• D. Lighter elements generally have lower number of stable isotopes.

Answer: (C)