The C stands for load range C, C is a 6 ply tire, there is also a D which is a 8 ply tire…
So do you have 2 P metric tires and 2 LT tires?? and are the LT’s C or E load range??
Since you are running 16" tires, that should make your trim level LS/LT, it calls for a basic P235/65R16..
No XL, C, D, E, just basic run of the mill all season tire…
EDIT: Yeah never mind, I had forgotten about the C=Commercial thing… oops…