Electronic configuration of Cu is [Ar] 3d10 4s1. Which rule is violated in this configuration?

• A. Aufbau Principle
• B. Hund‚Äö√Ñ√∂‚àö√ë‚àö¬•s Rule of Maximum Multiplicity
• C. Pauli‚Äö√Ñ√∂‚àö√ë‚àö¬•s Exclusion Principle
• D. None of the mentioned