[Q] What's the best way to remove all data? topic

My Rezound is unlocked, rooted, stock rom and S-on. I want to sell it but first I want to remove all of my data and get it as close to factory as I can. From what I can gather the only way to get it back completely stock is to be S-off but that process seems a little much for me to try. Which of these 3 options is best for what I'm trying to do? A factory reset in the bootloader, a complete wipe of everything in TWRP or factory reset on the phone's settings? Thanks