How many degrees of castor does the nose wheel have?

The correct answer is 150°. The nose wheel's castor angle refers to the degree to which the wheel can swivel in relation to the aircraft's longitudinal axis. A castor angle of 150° allows for a significant range of motion, enabling better maneuverability during taxiing and ground operations. This degree of castor provides a balance between stability and the ability to turn effectively, which is crucial for navigating various ground conditions and handling the aircraft efficiently on the ground. The other options represent angles that are either too high or too low, which would not provide the operational advantages needed for an aircraft's ground handling.