Final answer:
The item in 'The Binding of Isaac' that recharges one room's worth of charge to your spacebar item upon taking damage is the Habit.
Step-by-step explanation:
In the game The Binding of Isaac, the item which has the ability to recharge one room's worth of charge to your spacebar item upon taking damage is A) Habit. When you take damage with the Habit equipped, it grants you one charge for your spacebar item.
This can be particularly useful for items that have a high charge requirement, but you would indeed need to take damage multiple times to fully recharge an item that requires more than one room worth of charges.