How is it that the human body is not quashed by the air pressure which is surrounded ?

Question

$\begin{array}{1 1} (a)\;\text{human body is under pressure by itself} \\ (b)\; \text{human body exerts pressure equal to that of air } \\ (c)\; \text{pressure exerted by human body nullifies that of air} \\ (d)\; \text{all the above} \end{array}$