[Grammar] When you have decided

[shibli.aftab]

When you have decided on the option you'd like to use, please call me back.
When you will have decided on the option you'd like to use, please call me back.
When you will decide on the option you'd like to use, please call me back.
When you decide on the option you'd like to use, please call me back.

Which sentences are correct? What are the differences between them?

 

[Rover_KE]

Only 1 and 4 are grammatical.

There's no difference in meaning.