Option 1 -> "along" suggests walking beside the field rather than traversing it, and "over" implies going above the forest, which is illogical for hikers.
Option 2 -> "around" means avoiding the field by its perimeter, and "under" makes no sense for moving through a forest.
Option 3 -> "into" could work for entering the field, but "beside" means walking alongside the forest rather than entering it.
Option 4 -> "across" perfectly describes traversing the open field from one side to another, and "through" appropriately describes navigating within the dense forest.
Hence, Option 4: across, through -> These prepositions create a logical sequence of movement where hikers first traverse the open space of a field and then navigate their way within the dense forest -> correct