Final answer:
The correct square to calculate rafter lengths is B) Framing square, a tool specifically designed for roofing and framing calculations, offering precision for such carpentry tasks.
Step-by-step explanation:
To calculate rafter lengths for a construction or carpentry project, the correct square to choose would be B) Framing square.
A framing square is specifically designed for the tasks related to framing, including calculating angles and lengths for roof rafters. While a speed square, also known as a rafter square, can be used for smaller projects and marking cut lines, a framing square offers comprehensive features necessary for precise calculations. A combination square, on the other hand, is more commonly used for ensuring 90-degree angles and measuring short distances accurately.