Evaluate the indefinite integral:
∫ (1)/((3x+1)²)dx
a. -(1)/(3(3x+1))+C
b. (1)/(3)ln((3x+1)²)+C
c. (1)/(3(3x+1))ln((3x+1)²)+C
d. -(6)/((3x+1)³)+C
e. -(3)/((3x+1))+C