What does an NMR graph represent?

Question 1 options:

	The concentration of a particular chemical compound in the larger sample
	The strength of the external magnetic field required to prevent protons from spinning when subjected to high energy radio waves
	The number of atoms induced to spin by a particular frequency of radio energy
	The energy required to cause a partially shielded proton to flip from the more stable orientation to the less stable orientation in an external magnetic field