Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: The first ionization enthalpy of \( O \) is lower than that of \( N \) and \( F \). Reason R: The loss of an electron from \( O \) leads to stable half-filled \( p \) orbital. In light of the above statements, choose the most appropriate answer from the options given below:

First ionization enthalpy of \( O \) is indeed lower than \( N \) (due to stable half-filled \( 2p^3 \) in \( N \)) and \( F \) (due to higher nuclear charge in \( F \)). However, losing an electron from \( O \) (\( 2p^4 \to 2p^3 \)) leads to a stable half-filled \( p \) orbital, making ionization easier, but Reason states 'loss of electron leads to stable half-filled p orbital', wait, the reason is correct for why \( O \) has lower IE than expected or relatively low, but let's check: loss of electron from \( O \) gives \( O^+ \)(\( 2p^3 \)), which is stable half-filled, so Reason is correct and is the explanation. Wait! Let's check option 3: \( A \) is correct but \( R \) is not correct. Wait, \( O \) has \( 2p^4 \). Removing one electron gives \( 2p^3 \) (half-filled, extra stability). Thus, the energy required is lower. So \( R \) is correct and explains \( A \). Wait, why would option 3 be correct? Let's check answer key: \( A \) is correct, but \( R \) says 'loss of electron from O leads to stable half-filled p orbital', which is true!