Which of the following correctly used a semicolon?

There are many things that you can do to lessen your test anxiety, if not avoid it completely. first, make sure that you've read each lesson and prepared for the test appropriately. if you've gone over everything, there is no need to feel afraid of the test because the teacher cannot ask you anything you don't already know. it is also important to take a lot of breaks to let your brain rest a bit - so you should study for about 40-50 minutes, then make a 10 minute break where you can stretch or check your social media. i believe these strategies are important because they will you reduce your stress levels and make you realize that you are panicking for no reason.