Why is B incorrect?

@Meharan

@davidmaya, Since it is a could be true question, four of the answer choices are MUST BE FALSE/ CANNOT BE TRUE and only one could be true. Let's diagram this question - if the only message left by P is #5, which of the following could be true: P __ __ __ __ __ __ 1 2 3 4 5 6 Per rule (1), we know that H cannot be #1, eliminate (A) Let's consider (B) - T left exactly two messages. There are two possible scenarios: 1. If F left any messages, then per rule (5), we know that any T must follow any P, thus it is impossible for T to leave more than one message and it has to be #6, and that is why the hypothetical order of T H F L P T violates rule (5) and CANNOT BE TRUE. 2. If F left no messages, then if T leaves exactly 2 and P exactly 1, all the remaining parties have to leave 1 message each - G, H & L but per rule (4), G -> F& P and that brings us back to scenario 1 above, which we already determined is impossible, thus we can eliminate this answer choice (B). We could eliminate this option even faster using the inference from our initial setup: if G left any messages, everyone leaves exactly one message. Let's consider the rest of the answer choices: Per rule (6), we know that P -> H & L, H>> L and since H cannot be #2, L cannot be #2 - eliminate (D). Let's consider (E) - F left 3d and 4th messages: H F F P L __ __ __ __ __ __ 1 2 3 4 5 6 Per rule (5), we know that F -> P & T, P > T, but we have no space to fit T because it must go to #6 and that is also the only spot that L could go in because L must come after H and H cannot be #1 per rule (1). Thus, (E) cannot be true. Does that make sense? Let me know if you have any further questions.