a. From mu = g*muN*I /(hbar) we get:
g = mu*hbar/(mu_N*I)
which we can fill in with the values -0.5940(3) = mu (GS) and -0.766(3) = mu(245keV) and a spin of 1/2 for GS and 5/2 for 245keV.
Using the same formula we get
b. g = 2*hbar*mu_B/mu_N
c. mu = -3.826*(1/2)*mu_N/hbar