Select the phrase/connector from the given three options which can be used in the beginning (to start the sentence) to form a single sentence, implying the same meaning as expressed in the sentence.
He did not even tell his parents that he was going to apply for the exam because he knew that they will not agree with his decision.
1. To begin with
2. Firstly
3. One thing
1
Only 1
2
Only 2
3
Only 3
4
Both 2 and 3
5
Both 1 and 3