What is iodine-135 and its relation to xenon poisoning?

• A. Iodine-135 decays to xenon-135, and together they contribute to poisoning that reduces reactivity over time.
• B. Iodine-135 is a stable material that blocks neutrons for the life of the fuel.
• C. Iodine-135 enhances reactivity by producing extra neutrons.
• D. Iodine-135 is unrelated to xenon poisoning.

Answer: (A)