Standard hooks for deformed bars in tension are either what degrees?

The correct answer focuses on the standard hook configurations used for deformed bars in tension, specifically the common angles that are employed to ensure adequate anchorage of the reinforcing bars within concrete.

Standard hooks for deformed bars, which are critical for providing bond strength and ensuring that the bars develop their full design strength, are typically formed at either 90 degrees or 180 degrees. The 90-degree hook allows the bar to extend, providing hold against tensile forces, while the 180-degree hook is often used to loop back around, creating a secure anchorage point.

Understanding these angles is essential for professionals working in reinforced concrete design and construction, as using improper hooks can lead to structural failures or inadequacies in load-bearing capacity. The other options provided do not reflect standard practice for deformed bar hooks, which typically revolve around the 90-degree and 180-degree configurations.