Correct Response: B. A developing low pressure system typically has a warm front marking the leading boundary of relatively warm moist air and a cold front that marks the leading edge of colder air wrapping around the developing low pressure system. This is the process of cyclogenesis that leads to storm formation. When the faster moving cold front catches up with the warm front, it forces the less dense warm air upward, triggering precipitation along the now occluded front. Occluded fronts do not develop when one warm front catches up with another (A, C) or when a cold front catches up with another cold front (D). In all of these examples the similar fronts would typically reinforce each other and not form a new kind of front.
