The correct option is A mm of Hg
Answer is B.
The standard atmosphere is a unit of pressure equal to 101325 Pa or 1013.25 hectopascals or millibars. Equivalent to 760 mm Hg (torrcelian), 29.92 in Hg, 14.696 psi. (The pascal is a newton per square meter or in terms of SI base units, kilogram per meter per second-squared.)