In a doubly-reinforced beam if c and t are stresses in concrete and tension reinforcement, d is the effective depth and n is depth of critical neutral axis n, the following relationship holds good

A

$$\frac{mc}{t} = \frac{n}{(d - n)}$$

B

$$\frac{m + c}{t} = \frac{n}{(d + n)}$$

C

$$\frac{t + c}{m} = \frac{(d + n)}{(n)}$$

D

$$\frac{mc}{t} = \frac{d - n}{(t)}$$