Which isn't true about 13C NMR spectroscopy?
a. Each distinct carbon produces a single peak 13C NMR spectrum.
b. Splitting of signals into multiple peaks is not observed in routine 13C NMR spectra.
c. Decreased electron density around an atom shields the atom from the magnetic field
d. Larger mass of samples is usually required.
e. 13C spectra are usually less complex and easier to interpret than 1H NMR