Which setting should you turn off to stop your iPhone from automatically joining a network...

InSettings > Wi-Fi, tapping a network’s info (i) shows theAuto-Jointoggle. Disabling it prevents the iPhone from automatically connecting to that network, even if previously joined.

Option A: Ask to Join Networks prompts for new networks, not known ones.

Option B: Auto-Link isn’t an iOS setting.

Option C: Preferred Networks isn’t a toggleable option.

Option D: Correct—controls auto-connection.References: Apple Support - "Join a Wi-Fi network on iPhone" (support.apple.com/HT202831).