At a junction, currents I1=3A and I2=2A enter, while current I3 leaves. Using the sign convention that currents entering are positive, which equation correctly applies Kirchhoff’s current law?
a) I1+I2+I3=0
b) −I1−I2+I3=0
c) I1+I2−I3=0
d) I1−I2+I3=0