Which of the following is not a function

Answer:
Ang tamang sagot ay nandito sa naka-attach na picture
Explanation.
A function is either one-to-one or many-to-one.
Sa Case ng Pangalawang A (na Letter B. dapat yun typo lang ata - yung may - 4 at 7 sa left side as given) ay one-many yung relationship nito so hindi ito function.
Final Answer: Yung letter B (yung typo na pangawalang A)