A thin cylindrical shell of diameter (d) length ($$l$$) and thickness (t) is subjected to an internal pressure (p). The longitudinal stress in the shell is
A
$$\frac{{{\text{pd}}}}{{\text{t}}}$$
B
$$\frac{{{\text{pd}}}}{{2{\text{t}}}}$$
C
$$\frac{{{\text{pd}}}}{{4{\text{t}}}}$$
D
$$\frac{{{\text{pd}}}}{{6{\text{t}}}}$$
Correct Answer: $$\frac{{{\text{pd}}}}{{4{\text{t}}}}$$