Comparing the equivalent expressions for the nuclear magnetic dipole moment operator in terms of the spin operator, I find the following relation between g and µ:
g = µ / I with µ given in terms of the nuclear magneton µ_N (or the Bohr magneton in case of the electron)
Based on this I get the following results:
A) g(groundstate) = -1.188, g(245keV) = -0.3064
B) g = 1/(1/2) = 2
C) µ = g I µ_N = -1.913 µ_N