The Total Numbers of Navy Personnel N (In Thousands)and Marines $N ( t ) = 0.194 t ^ { 3 } - 7.88 t ^ { 2 } + 12.9 t + 375$

The total numbers of Navy personnel N (in thousands) and Marines personnel M (in thousands) from 2000 through 2007 can be approximated by the models​ $N ( t ) = 0.194 t ^ { 3 } - 7.88 t ^ { 2 } + 12.9 t + 375$ and $M ( t ) = 0.031 t ^ { 3 } - 0.25 t ^ { 2 } + 6.7 t + 173$ ​ where t represents the year,with t = 0 corresponding to 2000.
Find and interpret $( N - M ) ( t )$ .
​

A) $( N - M ) ( t ) = 0.163 t ^ { 3 } + 7.63 t ^ { 2 } - 6.2 t + 202$ ,which represents the difference between the number of Navy personnel and the number of Marines personnel.
B) $( N - M ) ( t ) = 0.163 t ^ { 3 } - 7.63 t ^ { 2 } - 6.2 t - 202$ ,which represents the difference between the number of Navy personnel and the number of Marines personnel.
C) $( N - M ) ( t ) = 0.163 t ^ { 3 } - 7.63 t ^ { 2 } - 6.2 t + 202$ ,which represents the difference between the number of Navy personnel and the number of Marines personnel.
D) $( N - M ) ( t ) = 0.163 t ^ { 3 } + 7.63 t ^ { 2 } + 6.2 t + 202$ ,which represents the difference between the number of Navy personnel and the number of Marines personnel.
E) $( N - M ) ( t ) = 0.163 t ^ { 3 } - 7.63 t ^ { 2 } + 6.2 t + 202$ ,which represents the difference between the number of Navy personnel and the number of Marines personnel.