Know, because know is present tense as is the rest of the sentence.
Answer: Which (A)
It makes more sense with ‘which’ then any of the other options.
Are these reasons why you love summer break. If these are reasons, that you did a great job explaining them. I loved your article. Great Job!
- Dhruva;)
It makes it meaning full because of the view
That would be the imperative mood.