Correct Answer:
B. By the next person on the party list
When a seat reserved for women or non-Muslims falls vacant, it is typically filled by the next person on the party list. This mechanism ensures that the proportional representation for these reserved seats is maintained without the need for a costly and time-consuming fresh election. Reserved seats are allocated to political parties based on their general election performance, and the party then nominates individuals from its list. Options A, 'By a fresh election,' C, 'By the Prime Minister,' and D, 'By the Chief Election Commissioner,' are incorrect as they do not align with the constitutional procedure for filling such vacancies.