The correct answer is D. She wants to teach other people's kids, she thinks she will be good.
Step-by-step explanation:
According to grammatical rules, a comma without conjunction should not be used to link two or more independent clauses, this punctuation error is known as a comma splice. Additionally, this can be corrected by adding a conjunction or using a semicolon to replace the comma.
In the sentence "She wants to teach other people's kids, she thinks she will be good" comma splice occurs because the comma was used to separate two independent clauses- These are independent clauses because each section "She wants to teach other people's kids" and " she thinks she will be good" expresses a complete idea and contains a subject and verb.