█ Explanation █
A collective noun is a noun that refers to a group or amount.
Based on this reasoning the answer would be "One-eighth of my allowance goes to savings" since it refers to an amount of allowance earned.
Answer: Choice B
Hope that helps! ★ If you have further questions about this question or need more help, feel free to comment below or leave me a PM. -UnicornFudge aka Nadia