Since the output is web, RGB is choosen, but is there any difference between “Monitor RGB…” and “sRGB…”?
In Photoshop, they are both under
color settings > working spaces > RGB
They can be the same, or at least appear to be the same, depending upon your monitor calibration settings.
The Monitor RGB setting uses the calibration profile for your monitor. That may be sRGB or not. You could easily calibrate your monitor to be wildly different than sRGB.
The sRGB setting uses sRGB.