How to enable an optional mechanic for my game?

Okay, something I've been trying to plan out is an optional mechanic for my game, specifically it involves crafting stuff (Yanfly's Item Synthesis, but this question doesn't deal with problems with said plugin) like Alchemy, Smithing, Cooking, Farming, maybe Fishing/Mining enc. I'm working all that out slowly, so I have no problems with how to do it (thanks to Driftwood Gaming I'll probably just use a combination of his Farming System Tutorial and his Mining System plus help from you guys!). The thing is, I want to make it optional and I'm not sure what to do.

Do I...

1. Ask the player during a new game, "Do you wish to enable Crafting?" in a menu?

2. Have it listed in the Options that's never mentioned in text that can be turned on and off?

3. Have it brought up if you decide to check on a certain farm-y looking event and that sets up the tutorial and activates it automatically?

4. All three?

"But Little Adventurer", you're asking, "if you have items such as potions and food that you can just BUY in-game, why bother trying to create them which would be a longer process of getting ingredients and crafting the item, and even then it's possible to screw up said crafting and get a bad item instead of what you want than just buying them which the only detriment is possibly not having enough money?" Because I was thinking about giving benefits if you manage to raise said crafting skills. Like, say, for example, you can build up your Cooking skill and instead of just having a loaf of bread heal you for 15 HP, it does more HP than the standard bought one AND have it give you HP Regen as well.

So yeah, I think that'd be cool! :)