A. f(z) 1s analytic then U_x = V_y, U_y = -V_x

B. Polar C-R equation is \(\rm U_r=\frac{1}{r}V_0, U_0=-rV_r\)

C. Two curves are said to be orthogonal to each other when they intersect at acute angle at each of their points of intersection 

D. \(\rm \int_C\frac{dz}{z-1}=2\pi i\ where\ C:|z-1|=\frac{1}{2}\)

choose the correct answer from the options given below: