The figure shows a circular loop of radius \( a \) with two long pa...

The figure shows a circular loop of radius \( a \) with two long parallel wires (numbered 1 and 2) all in the plane of the paper. The distance of each wire from the centre of the loop is \( d \). The loop and the wires are carrying the same current \( l \). The
D current in the loop is in the counter-clockwise direction if seen from above.
(2014 Adv.)
When \( d \approx a \) but wires are not touching the loop, it is found that the net magnetic field on the axis of the loop is zero at a height \( h \) above the loop. In that case
(a) current in wire 1 and wire 2 is the direction \( P Q \) and \( R S \), respectively and \( h \approx a \)
(b) current in wire 1 and wire 2 is the direction \( P Q \) and \( S R \), respectively and \( h=a \)
(c) current in wire 1 and wire 2 is the direction \( P Q \) and \( S R \), respectively and \( h \approx 1.2 a \)
(d) current in wire 1 and wire 2 is the direction \( P Q \) and \( R S \), respectively and \( h \approx 1.2 a \)