Option A:
this.growl = () => { ... } inside the constructor creates a new function per instance.
For 1000 new Monster(), you get 1000 distinct growl functions, each stored on the instance itself.
Option B:
Monster.prototype.growl = () => { ... } attaches growl to the prototype.
All instances share the same single growl function via the prototype chain.
For 1000 instances, only 1 growl method exists in memory.
So: Option A → 1000; Option B → 1.
________________________________________