Which organization is known as the oldest code organization?

The correct answer is B, as the International Conference of Building Officials (ICBO) was established in 1927, making it the oldest among the listed organizations related to building codes. The ICBO played a significant role in creating and updating building standards and codes which laid foundational practices for construction safety and building integrity.

The ICC (International Code Council), established in 1994, is newer and formed to harmonize various building codes under a single set of codes. NFPA (National Fire Protection Association) focuses primarily on fire safety standards and was founded in 1896, which is notable but does not pertain directly to building regulation as broadly as ICBO. ANSI (American National Standards Institute) was established in 1918 and serves as a coordinator for standards but isn't specifically a building code organization, making it less relevant to this discussion. Thus, ICBO's long-standing history certainly justifies its standing as the oldest code organization in the context of property maintenance and construction codes.