Please choose the correct ending to complete the given sentence: Cars & Other Vehicles: [header] How to fix a broken bicycle chain [title] Take a picture, draw out, or memorize how the chain is currently attached. [step] Note how it moves in and out of the pulley wheels, if there are any. Chains wrap around the derailleur (shifting device in the back of the bike) in a particular, but not difficulty to understand, patter you'll need to replicate later.

Ending1: [title] Bolt the chain to your bike door, if needed. [step] Bolt the chain so it is loose, but make sure to make a straight line. Ending2: [title] Brush the chain/derailleur with a small toothbrush to remove any knots. [title] Detach the lower parts, if needed. Ending3: [title] Simply fasten the chain to the pulley pulley. [step] It's the hardest thing to do at this point, and you may have to select multiple parts. Ending4: Some chains are simply threaded on the gear. [substeps] If you work carefully you won't even need to remove the chain from the bike.

Answer format: ending1/ending2/ending3/ending4