An experiment consists of eight steps - H, J, K, L, M, O, P, and S - that all must be performed. Three days are allotted for the experiment. Each step requires exactly one morning or else one afternoon to be performed, and at most two steps can be performed during any given morning or afternoon. The following restrictions must be observed: J must be performed on the second day. P must be performed in the morning. K and M must be performed at the same time. J must be performed at some time after M has been completed and at some time after O has been completed. O must be completed at some time before P and at some time before S. If H and L are both performed on the first day, which of the following must be performed on the third day?

Explanation: **First Day (4 slots: 1st Morning, 1st Afternoon, total max 4 steps):** H and L are performed. Remaining slots for Day 1: 2. K and M must be together. J is on Day 2. M and O must be before J (Day 2). O must be before P (Morning) and S. Since K and M must be done together (taking 2 slots), and they must be before J (Day 2), K and M must be the remaining two tasks on Day 1. **Day 1: H, L, K, M.** **Day 2 (4 slots):** J is mandatory. M and O must be completed before J. Since M is done on Day 1, O must be done on Day 2 before J (if J is in the afternoon) or on Day 1 (which would displace K and M). Let's check Day 2: J (1 slot) and O (1 slot). **Day 2: J, O, (2 remaining slots).** P must be in the morning. O must be before P. The earliest P can be is 2nd Day Morning. J is on Day 2. If O is in the 2nd Day Afternoon, J must be in the 3rd Day, which contradicts the condition. Let's re-evaluate the constraint: \(J\) after \(M\) and \(O\). \(O\) before \(P\) (morning) and \(S\). If H, L, K, M are Day 1 tasks (4 slots filled). O must be on Day 2. J is on Day 2. To have O before P (Morning) and have all steps done: P must be after O. If O is Day 2 morning, P can't be Day 2 morning (P before O is false). If O is Day 2 afternoon, P must be Day 3 morning (P must be morning). Therefore, P must be on the third day Morning.