Brent was looking at his cell phone bill and saw that the total number of texts he has sent is tracked.

month texts
1 120
2 237
3 354
4 471

the function representing brent's texting per month is f(m) = 117m + 3. what does the 117 represent?

a. the number of texts at the start

b. the number of the month when brent was texting

c. the number of texts brent had in total

d. the number of the additional texts per month