The answer is the first definition. So, you'd want to select 1.
The reason for this is that A) we're not talking about a fish scale. You can't place a fish on another fish's scale and figure out it's the biggest catch. B) There's nothing in here at all about music. C) And lastly, the fisherman isn't climbing anything. He's weighing a fish.
I hope this helps.
-Toremi
