Answer:
1. The <u>lighthouse</u> is located in <em>North Carolina</em>.
2. <em>Herbert Greenley</em> built it to help<u> sailors.</u>
3. It helps them see during strong <u>storms</u>.
4. <em>Greenley</em> was proud of the <u>building</u> he created.
Explanation:
underlined text = common nouns
boldfaced, italicized text = proper nouns
Sentences 2 and 3 contain plural noun forms.