Nest Thermostats don't use jumper wires, so don't enter that into the Nest app during setup (i.e., don't select that you have an RC wire, just enter the RH wire). Looking at your wiring, it should be compatible. You won't see an option for a B/C wire. For your setup, it looks like that wire is a C (common) wire as you don't have a separate C terminal, the colour is blue, and you already have an O wire on a separate terminal. If you're unsure, I'd recommend checking your thermostat's manual if you still have it or look for it online to confirm.
Learn about thermostat jumper wires - Google Nest Help
Thermostat Compatibility - Google Store
