In which pair does the SECOND member have a higher first ionisation energy than the FIRST?

1. Option A: Na (496 kJ/mol) and Mg (738 kJ/mol). Mg comes after Na in period 3. 2. Across a period, ionisation energy generally rises with nuclear charge. 3. So Mg's ionisation energy is higher than Na's, consistent with the trend. 4. Option B: oxygen has lower ionisation energy than nitrogen due to N's half-filled p stability. 5. Option C: boron has lower ionisation energy than beryllium because of Be's filled 2s stability. 6. Option D: sulfur is below oxygen, so ionisation energy is lower not higher. 7. So only option A shows the second element with the higher first ionisation energy. _Source: Selina Concise Chemistry ICSE Class 10, Ch 1 'Periodic Table' (aplustopper.com extract)_