I don't have to justify anything to you.
I answered correctly because I've finished my exams last year, using the banks.
This being said if I remember correctly on the 737 as an example the vertical profile is managed with alt, vspeed, airspeed and elevator deflection.
It would also be possible to design a VNAV system based on the AoA or any other useful reference (es: accelerometers), but not without controlling the engines. Anything without engines control is not an automated VNAV system.