If the permissible compressive stress for a concrete in bending is C kg/m2, the modular ratio is_____________?

by
If the permissible compressive stress for a concrete in bending is C kg/m2, the modular ratio is_____________?

A. 2800/C
B. 2300/2C
C. 2800/3C(Correct)
D. 2800/C2