Which of the following describes the operation of a closed-loop EFI wideband oxygen sensor compared to a narrowband sensor?

1. A narrowband sensor is mechanical, while a wideband sensor is entirely electronic
2. A wideband sensor operates without needing to reach an operating temperature
3. A wideband sensor can measure the exact air-fuel ratio over a wide range (e.g. 10:1 to 20:1), whereas a narrowband sensor is only accurate right at stoichiometry (14.7:1)
4. A wideband sensor only measures exhaust gas temperature, not oxygen content