Assume that no accumulation of receptors occurs on the membrane or in the endosome. Solve for the steady-state value of rs in terms of kdeg, ke, vs, krec, and fr.

a) rs = vs / (krec + kdeg)
b) rs = vs / (krec + kdeg + ke)
c) rs = vs / (krec + ke)
d) rs = vs / (krec - kdeg - ke)