can you please help explain this question to me step by step

can you please help explain this question to me step by step?

Two identical coaxial circular coils carry the same current / but in opposite directions.
The magnitude of the magnetic field B at a point on the axis midway between the
coils is
(a) Zero
(b) The same as that produced by one coil
(c) Twice that produced by one coil
(d) Half that produced by one coil.

Solution

It is option c.

As the currents are in opposite direction the magnetic fields will be in the same direction. The total field twice the magnetic field in each coil. We has to use the right hand thumb rule to find the direction of magnetic field.