Way 1 · best default
So that's why
You loop back to your main point, so the answer sounds complete. Great in a speaking test.
Examples
So that's why I'd rather live in a small town.
The food, the people, the sea... so that's why I keep going back.
In a conversation
A: Why do you like your hometown?
B: It's quiet, my family's there, and the food's amazing. So that's why I love it.
Common mistake
Not: It's quiet and the food is good. That's all.
Say: It's quiet and the food is good, so that's why I love it.
"That's all" stops the answer dead. Going back to your main point makes it sound finished.
