Answer:
Curled fingers will give the direction of magnetic field.
Step-by-step explanation:
The right hand thumb rule states that hold any current carrying conductor in your right hand such that the thumb is pointing in the direction of electric current. Then the curled finger will give the direction of magnetic field.
For example : when the current in the wire is flowing towards right, then the curled finger will give the direction of magnetic field i.e. the field is towards bottom.
Hence, the correct option is (c) fingers.