Staging of a Lung Cancer Is Based on Which of These

Staging of a lung cancer is based on which of these criteria?
1) L, for location of the tumor
2) M, for extent of metastasis
3) N, for lymph node involvement
4) T, for extent of the primary tumor

A) 1, 4
B) 2, 3
C) 2, 3, 4
D) 1, 2, 3