Imagine a universe where time flows differently on different planets. Planet A experiences time at twice the rate of Planet B. A team of scientists from Planet A sets off on an expedition to Planet B, spending ten years traveling there and back. How much time will have elapsed on Planet B when they return?

A) Five years

B) Ten years

C) Fifteen years

D) Twenty years

Explanation:

The key to solving this puzzle is to understand that the flow of time is relative and dependent on the observer's frame of reference. For the scientists on Planet A, ten years pass during their journey. However, time flows twice as slowly on Planet B, so only five years will have elapsed there when the scientists return.

Therefore, the correct answer is A) Five years.