A nuclear magnetic resonance, or NMR, spectrometer is an instrument that can be used to characterize molecules based upon the excitation of inner shell electrons. the behavior of the nuclei of certain atoms in a magnetic field. the nuclear radiation emitted by certain molecules. vibrations of portions of the molecule brought about by the absorption of infrared radiation.

The correct answer is A)

Explanation:

An NMR or Nuclear Magnetic Resonance Spectrometer is an equipment that can be used to study the nature of molecules after their nuclei have been excited with the use of radio waves. Radio waves generated is converted into nuclear magnetic resonance.

The resonance produced can be recognized or decoded by special radio receivers.  

Besides recognizing the molecular structure of a chemical compound, it's purity and its content can also be analyzed.

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c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.