Question

select all of the common nouns.
martin luther king, jr. day is a holiday that falls on the third monday in january.

Explanation:

A common noun is a general name for a person, place, thing, or idea, not a specific one. Proper nouns are specific names (like "Martin Luther King, Jr. Day", "Monday", "January" which are specific names of a holiday, day of the week, and month). "Holiday" is a general term for a day of celebration or rest, "Monday" here? Wait no, "Monday" is a proper noun (name of a specific day). Wait, let's re - evaluate: "Martin Luther King, Jr. Day" is a proper noun (specific holiday). "holiday" is a common noun (general term for a type of day). "Monday" – wait, days of the week are proper nouns? Wait, no, actually, "Monday" is a proper noun as it's a specific name. Wait, the sentence: "Martin Luther King, Jr. Day is a holiday that falls on the third Monday in January." So proper nouns: Martin Luther King, Jr. Day, Monday, January. Common nouns: holiday. Wait, but "Monday" – is "Monday" a common or proper noun? Days of the week are proper nouns because they are specific names. So in the sentence, the common nouns are "holiday". Wait, but let's check again. A common noun refers to a class of people, places, or things. "Holiday" is a general term (a type of day), while "Martin Luther King, Jr. Day" is a specific holiday (proper noun), "Monday" is a specific day of the week (proper noun), "January" is a specific month (proper noun). So the common noun here is "holiday".

Answer:

holiday