Three long parallel wires form the vertices of an equilateral triangle of side 4cm. Currents of 10A, 5A and 7A flow along +z, +z and −z directions respectively through the three wires. A circular Amperian loop of radius 6cm is centred at the triangle’s centroid and lies in the plane of the triangle. What is the net current enclosed by this loop?
a) 22A
b) 15A
c) 8A
d) 2A