D

Step 1: Understand that the magnetic field intensity () at a point P due to a circular coil is given by the Biot-Savart law, which states that the magnetic field due to an element of current-carrying conductor is directly proportional to the current and inversely proportional to the distance from the element to the point of interest.
Step 2: In the case of a circular coil, at a certain point outside the coil, the contributions from all other elements of the coil cancel each other due to symmetry.
Step 3: If we consider point P, which lies along the axis of the coil but is outside it, the magnetic fields produced by each segment of the wire of the coil at point P will, due to symmetry, cancel out entirely.
Conclusion: Therefore, the net magnetic field intensity at point P is zero.
Therefore, D.