At a junction P of a circuit, currents I1 and I2 are taken as flowing into the node while current I3 is taken as flowing out of the node. According to Kirchhoff’s current law, which of the following equations is correct?
a) I1+I2+I3=0
b) I3=I1−I2
c) I1+I2−I3=0
d) I1=I2+I3