The self weight of a steel roof truss is $$\frac{N}{m^{2}}$$ may be computed by :(span =l)

A

$$(\frac{l}{3})+5$$

B

$$[(\frac{l}{3})+5] \times 10$$

C

$$[(\frac{l}{3})-5] $$

D

$$[(\frac{l}{3})-5] \times 10$$