Final answer:
The proper noun from the given options is 'congressman John Lewis' as it specifically names an individual, and proper nouns are always capitalized.
Step-by-step explanation:
The proper noun in the options provided is c) congressman John Lewis. A proper noun is a specific name for a particular person, place, or thing and is always capitalized. In this case, 'congressman John Lewis' refers to a specific individual, which makes it a proper noun. Option a) 'him' is a pronoun, b) 'swimming pool' is a common noun, and d) 'politician' is a common noun referring to any person in the profession of politics.