The circumferential (hoop) stress in a thin walled cylinderical vessel under internal pressure is
A
$$\frac{{{\text{pd}}}}{{2{\text{t}}}}$$
B
$$\frac{{{\text{pd}}}}{{4{\text{t}}}}$$
C
$$\frac{{{\text{pd}}}}{{\text{t}}}$$
D
$$\frac{{{\text{pd}}}}{{3{\text{t}}}}$$
Correct Answer: $$\frac{{{\text{pd}}}}{{2{\text{t}}}}$$