Question about my Pantech Impact?

Does anyone know which option I choose to reset my phone? I recently stopped getting notifications on my cell if I receive a new text message, as well as getting error when I check my email on it. There are three options to choose from on my cell to reset but I'm not sure which one to pick--there's master reset, master clear and external memory reset. The last time I reset my phone, i mistakenly chose the wrong option (don't remember which one), which resulted in me losing all of my pics, music and wallpapers. Can anyone tell me which one to go to so I can reset my phone without losing all of my personal items?