I have a question regarding the interaction of the Long Jump rules (PHB, p182) and the Using Different Speeds rules (PHB, p190). The first paragraph of the rules for long jumping concludes with this sentence:
“Either way, each foot you clear on the jump costs a foot of movement.”
My initial thought was to assume “movement” here means walking speed. However it becomes ambiguous when the jumping creature lacks a walking speed, or has multiple movement modes. Is jump distance meant to be constrained specifically by walking speed, or can each “foot of movement” be subtracted from other speeds?
I see three possible interpretations:

Jump distance is subtracted from your walking speed only.

Jump distance is subtracted from one of your speeds (but not necessarily walking speed).

Jump distance is subtracted from all of your speeds simultaneously.
Option 1 results in a world in which many aquatic creatures cannot jump at all, so I don’t think it makes sense. I think option 2 makes the most sense, but also leads to some odd results at the extremes. Option 3 has the same problems as option 1, and also is problematic because it essentially doublecounts the jump distance against every speed.
As an example: a dolphin has a strength of 14, a speed of 0 feet, and a swim speed of 60 feet. Could a dolphin swim 10 feet to get a “running start” before jumping 14 feet horizontally out of the water and through the air (subtracting this distance from its swimming speed)? I would presume that dolphins can use their swimming speed instead of walking speed for jump distance, because the alternative would be that dolphins cannot jump at all (as they would be constrained to a distance of 0 feet by their walking speed).
Now, let’s complicate the example by introducing multiple speeds: A giant octopus has a strength of 17, a speed of 10 feet, and a swim speed of 60 feet. I would assume it could jump in a manner similar to the dolphin using only it’s swim speed – but what if it were on land? Could the octopus use its 10 feet of walking speed to get a running start, and then jump 17 feet horizontally (subtracting the distance of the jump from its unused swimming speed)?
Another example involving climbing speed instead: Can a brown bear (strength 19, speed 40 feet, climbing speed 30 feet) run 40 feet and then jump 19 feet horizontally (subtracting those 19 feet from its unused climbing speed)? Or, to go the other way, could it climb 30 feet up a tree and then jump 19 feet horizontally (subtracting the jump distance from its unused walking speed)?
So, which interpretation is correct? Or is there another interpretation I’ve missed?