As per Indian standard system of limits and fits, there are 18 grades of fundamental tolerance. The grades of fundamental tolerance ranges from _______.
1
IT1, IT2, .........., IT18
2
IT0, IT1, IT2, ............... IT17
3
IT01, IT0, IT1, IT2, ................ IT16
4
IT001, T01, IT0, IT1, IT2, .................IT15