I got a new laptop, will it wipe out my iPhone's memory?

I recently got a new laptop, it's a Macbook Air and I'm syncing my phone to my iTunes account. I finished syncing it and I went to my music. A popup came up and it said I have changed the settings for my iPhone and if I would like to apply these changes. What will happen if I say yes? I haven't answered yet.

It will delete all your music and apps

It will delete music not bought from itunes. Apps should stay unless you jailbroke to get the apps illegally. Photos are saved.