In which occupancy group(s) are two exit access doorways required when the occupancy load exceeds 49?

The requirement for two exit access doorways when the occupancy load exceeds 49 is primarily associated with occupancy types that involve higher public interaction and are subject to specific safety regulations. In assembly occupancies, which include places such as theaters, auditoriums, and conference halls, the potential for large numbers of people gathered in one space necessitates multiple exits to ensure safe evacuation.

Business occupancies, where people also gather for occupational purposes, similarly require adequate means of egress due to potential high occupancy levels, particularly in offices and retail environments. Mercantile occupancies, consisting of stores and similar spaces where goods are sold, also fall under these guidelines, as they can attract a large number of patrons.

The other groups listed in the other choices either don't present the same level of risk in terms of public gatherings, or their specific codes may not emphasize the same requirement for multiple exits based on occupancy load, especially when looking at categories like residential or agricultural settings, which typically have different safety standards or lower occupancy thresholds before requiring additional exit access.