a= 2, b= 5, c=5, d=6 3. Let f(z) = (z - a)G(z - b) where S(z) is the imaginary part of the complex number z. (a) Substitute the values of a and b and write down f(z). (0 points) (b) Is f(z) differentiable everywhere? Find a point where it is differentiable. If no such point exists, report that too. (4 points) (c) "If v is a harmonic conjugate of u, then u is also a harmonic conjugate of v." Is this statement true or false? Explain in your own words. (1 point)