Which of these fits gap 21?

Directions: Complete this passage by selecting the most suitable option for the corresponding gap.

The neighbourhood police officer in his shining cap and uniform has a very _____(21)______ job.   He helps the community by seeing that everybody _____(22)____ the law. He takes extra care to protect the young and the old from bad people. He helps the traffic, _______(23)______ catches thieves. Whenever there is any reason for you to be______(24)______, you can call him to help you.