Tolerance is a problem when using Nitroglycerin, which of the following is true.. Dosing schedule may affect tolerance

Tolerance is a problem when using Nitroglycerin, which of the following is true:
a- Tolerance doesn't occur in young patient
b- Over 50 years patient doesn't develop tolerance
c- Dosing schedule may affect tolerance***
d- Isosorbide dinitrate doesn't develop tolerance.