The correct option is B P−(g)→P(g)+e−
Si− has an outer electronic configuration of 3s2 3p3. Since it is half filled, removing an electron from this species requires more energy.
P− has an outer electronic configuration of 3s2 3p4. Removing one electron from this species will require very less energy because on removing an electron it attains the stable half filled configuration.
S−and Cl− have an outer electronic configuration of 3s2 3p5 and 3s2 3p6 respectively. The energy required to remove one electron from both of these species will be more (especially the chloride ion since it has a noble gas configuration).