The correct option is B Hydrogen sulfide
Acid gas and sour gas are often mistakenly used to describe acid gases, the terms are not the same thing. A sour gas contains high amounts of hydrogen sulfide, while an actual acid gas contains any of the acidic gases. When found in natural gas, hydrogen sulfide can be considered both a sour gas and an acid gas. Carbon dioxide, however, is an acidic gas but not technically a sour gas.