Which of the following have least electron affinity?

EA increases (more negative value) along the period (→). But there is an exception in EA s value of N and CTherefore, EA's of N (less negative) < C (more negative) due to half-filled p-orbitals in N. Addition of electron will be difficult.So, less energy is released in comparison to N.Increasing order of EA is from less negative to more negativeN < C < O < F ⇓(least EA)