Final answer:
The sentence does not follow capitalization rules in English. Proper nouns, including names, should be capitalized.
Step-by-step explanation:
The sentence 'Her best friend's name is tonya' does not follow capitalization rules. In English, proper nouns, which include names, should be capitalized. In this case, 'tonya' should be capitalized to 'Tonya' to adhere to capitalization rules. Here's an example of how the sentence should be written: 'Her best friend's name is Tonya.'
Learn more about Sentence capitalization in English