At steady state, a reversible heat pump cycle discharges energy at the rate q˙h to a hot reservoir at temperature th, while receiving energy at the rate q˙c from a cold reservoir at temperature tc. (a) if th = 13°c and tc = 2°c, determine the coefficient of performance. (b) if q˙h= 15 kw, q˙c= 8.75 kw, and tc = 0°c, determine th, in °c. (c) if the coefficient of performance is 20 and th = 27°c, determine tc, in °c.