Final answer:
The radius of a flying saucer with a diameter of 17 feet is 8.5 feet, which is half the diameter.
Step-by-step explanation:
The student has asked about the radius of a flying saucer, given that its diameter is 17 feet. The radius is always half of the diameter. Therefore, if we take the diameter (17 feet) and divide it by 2, we get 8.5 feet. So, the correct answer is a) 8.5 feet.