The figure shown the cross section of a long cylindrical conductor through which an axial hole of radius `r` is drilled with its centre at point `A`. `O` is the centre of the conductor.
If the identical hole were to be drilled centred at point `B` while maintaining the same current density the magnitude of magnetic field at `O`

Options

A. will increase
B. will decrease
C. will remains the same
D. May increase of decrease depending on the value of `r`.

Explanation

Adding two vectors of same magnitude with an angle of `120^(@)` between them yields another vector of the same magnitude.