premise: A courier delivers exactly eight parcels—G, H, J, K, L, M, N, and O. No two parcels are delivered at the same time, nor is any parcel delivered more than once. The following conditions must apply: L is delivered later than H. K is delivered earlier than O. H is delivered earlier than M. O is delivered later than G. M is delivered earlier than G. Both N and J are delivered earlier than M. Which one of the following must be true?
hypothesis: At least four parcels are delivered earlier than M is delivered.