43. Which of the following statements best explains the information we can gain from mass spectrometry?
(A) It allows us to determine the number of protons in a compound.
(B) It allows us to determine the kinds of functional groups in a compound.
(C) It allows us to determine the molecular weight and the mass of some fragments of a compound.
(D) It allows us to determine the presence and nature of a carbocation in the compound.