Explanation:

- To practise yoga, I usually wake up when the sun ______.

- Option 1: "Covers" means to put something over or on top of something else. It doesn't make sense in this context.

- Option 2: "Disappears" refers to not being visible anymore, often when the sun goes down. It doesn't fit in the context of waking up for yoga.

- Option 3: "Rises" means the sun is coming up in the morning. This is when people typically start their day and is the perfect time to practice yoga.

- Option 4: "Sets" describes when the sun goes down in the evening. This doesn't align with waking up for yoga.