on the reset screen of the yaesu ftm-300dr what is option 5?

On the reset screen of the Yaesu FTM‑300DR, option 5 is “APRS RESET.”

This APRS reset clears the APRS-related settings and data (such as APRS configuration items and logs) without performing a full factory reset of the entire radio.

“Press and hold the [F(SETUP)] key → [RESET] → [5 APRS RESET].”

So if you select option 5, you are only resetting the APRS functions, not wiping all memories or general settings.

Information gathered from public forums or data available on the internet and portrayed here.