Solutions: Option B
Whatever that goes in has to come out. With this basic concept, you will be able to solve this question easily.
Ignoring the unknown branch,
Total current going into O = 8A + 6A = 14A
Total current going out of O = 12A + 4A = 16A
Hence in order to be equal, 2A must be flowing in direction PO.
Hence answer is B.