Question

Electron affinity of sulphur is (a) more than O and Se

Answer 1

oxygen has a lower electron affinity (as shown the picture below), because it has a smaller atomic radius than sulfur and thus the electrons experience significant electron-electron repulsions.
However, this not the case for sulphur and selenium or chlorine bromine Because of Sulfur's and Chlorine's smaller atomic radius compared to Selenium and Bromine, the incoming electron should also experience a slight electron-electron repulsion (just like it does with oxygen), so Se ad Br should have a higher electron affinity.