You are not answer 1 and 3, and answer 2 your answer has been written all in English.
Your answer 2, I can use your opinion to keep my knowledge and skill.
Your answer 3, you do not recommend to give reference such as the website ,book, journal or magazine that you used it. In addition to your answers, I think we should have an English translation from our experience and knowledge that we have with it.
Anyway, I think you will be careful to read and answer with English course.
However, I think that your English writing, grammars are correct. I hope you will succeed in the course and according to your expectations.