Fill in the blanks with the right verb forms to make it a meaningful sentence.
If you ______ hard in your school days, you ______ this examination today.

The given sentence is an example of a third conditional.
Third Conditional: The third conditional, also called the "Past Unreal" conditional is used to describe unreal situations in the past.
It is often used to express regret about the past because the hypothetical situation that it describes is now impossible as a consequence of another past action.
The structure of it as follows: If + past perfect, would + have + past participle.
Example: If we had won, I would have been happy.
Therefore, as per the points mentioned above, we find that the correct answer is Option 3.