Final answer:
The proper nouns in the sentence given are 'Lord' and 'Rings' as they are part of the title of the book series 'The Lord of the Rings'. 'Myself' is a reflexive pronoun and 'trilogy' is a common noun, not a proper noun.
Step-by-step explanation:
The proper noun(s) in the sentence: "I was very proud of myself when I finished the Lord of the Rings trilogy" are Lord and Rings, are 'Lord,' 'Rings,' and 'trilogy.' Proper nouns are the specific names of people, places, or things, and they are always capitalized. In this sentence, 'Lord' refers to the title of a book and should be capitalized, 'Rings' refers to a specific set of books and should also be capitalized, and 'trilogy' refers to a specific series of books and should be capitalized as well.
which are part of the title of the book series. Therefore, the correct answers are options b (Lord) and c (Rings). A proper noun is the specific name of a person, place, or thing and is always capitalized. 'Myself', being a reflexive pronoun, and 'trilogy', a common noun referring to a series of three books or movies, do not qualify as proper nouns in this context.