When applying Kirchhoff's Current Law (KCL) at nodes 1, 2, 3, and 4 with corresponding voltages V, W, X, and Y, how would the four nodal equations be formulated symbolically
a) 4I 1+I 2=I 3+I 4
b) V−W=X−Y
c) V+W=X−Y
d) I 1−I 2=I 3+I 4