Foundation anchor bolts should extend at least ____ inches into masonry or concrete.

The correct answer regarding the extension of foundation anchor bolts into masonry or concrete is that they should extend at least 7 inches. This requirement is primarily based on structural integrity and safety. Anchor bolts are critical components that secure a building's framework to its concrete foundation, allowing the structure to withstand lateral forces like wind and seismic activity.

The 7-inch minimum extension ensures that the bolt has enough embedment depth in the concrete or masonry to achieve maximum holding power. This depth also reduces the risk of shear failure or pullout, particularly in situations where loads may exert significant force on the structural connections. Proper embedment helps ensure the longevity and resilience of the building's framework.

While the other options suggest different lengths, they do not meet the recognized standards for adequate embedment, potentially compromising the stability and safety of the structure. Consequently, the established 7-inch standard is an essential guideline for achieving effective anchorage in concrete or masonry foundations.