Explanation:

- Option 1: Priyadarshini Mattoo case

- Priyadarshini Mattoo, a 25-year-old law student, was murdered in 1996.

- The case involved her fellow student Santosh Kumar Singh.

- Singh was initially acquitted but later found guilty by the Delhi High Court in 2006.

- Option 2: Santosh Kumar Singh Vs. CBI

- This case is directly related to the Priyadarshini Mattoo murder.

- The Supreme Court upheld Singh’s conviction in 2010.

- It is the legal representation of the same case.

- Option 3: Both A and B

- Both options relate to the same incident involving the murder of a law student.

- Priyadarshini Mattoo case and Santosh Kumar Singh Vs. CBI refer to the same situation.

- Option 4: None of the above

- Invalid because both Options 1 and 2 pertain to the murder of a law student.

- Correct Answer: Option 3: Both A and B