Four handbags and three school bags costs $2000 and cost of handbag is thrice as much as schoolbags. If cost of school bag is 'a' then the derived equation will be _____ ?

A. 3(4a) + 3(3a) = 2000
B. 3(4a) – 3(3a) = 2000
C. 3(4a) – 3a = 2000
D. 3(4a) + 3a = 2000

Four handbags and three school bags costs $2000 and cost of handbag is thrice as much as schoolbags. If cost of school bag is ‘a’ then the derived equation will be _____ ?