Joists framing into the side of a wood girder shall bear on wood ledger strips of what minimum dimensions?

The correct choice highlights that joists framing into the side of a wood girder must bear on wood ledger strips with minimum dimensions of 2 inches by 2 inches. This specification is established to provide adequate support for the joists and ensure proper load distribution.

Using a ledger strip with dimensions of 2 inches by 2 inches is sufficient to accommodate the load from the joists while also allowing for proper nailing or fastening to the girder. This size strikes a balance between structural integrity and material efficiency, ensuring the framing is both strong and practical without unnecessarily using larger dimensions that could increase costs or weight without benefit.

When considering the other options, they either exceed the necessary dimensions or do not conform to the established construction practices that prioritize efficiency, safety, and code compliance. Such specifications in building codes and best practices guide builders and contractors in ensuring that frames are both safe and sound without using excess material.