From a fully-filled vessel of 12-litre capacity, to bring 6 litres of water into an empty vessel of 8-litre capacity, what is the minimum number of times water must be poured, given that an empty 5-litre vessel is also available for use?
You have the answer. Trap Analysis is why the other three were written.
Not a worked solution repeated four times — the specific reasoning error each wrong option was built to reward, and why this one tests execution slip.
See pricing50 are analysed free — try those first.