Bihar Police Constable Model Paper 1

All the given options are modal auxiliaries. They facilitate the main verb for suggesting potential, expectation, permission, ability, possibility, and obligation.

• should indicates obligation and probability.
• shall express a strong assertion or intention or expressing the future tense.
• May and might both indicate possibility but might suggest that there is less possibility than may.
• Here, 'duty' is mentioned which shows its obligation. So, 'should' is the most suitable alternative.