Please assist with the following questions (Engine Diagnostics)

10.   A vehicle fails an HC emission test at idle and 2,500 rpm, and the engine has an acceleration stumble. The heated oxygen sensor (HO2S) voltage is 0.1–0.3 volts on a scan tool, and the injector pulse width is high. No diagnostic trouble codes (DTCs) are found. When propane is directed into the air intake, HO2S voltage immediately increases and the injector pulse width decreases. The most likely cause of this problem is
 
A. a defective powertrain control module (PCM).
B. an opening in the O2 sensor signal wire.
C. a defective O2 sensor.
D. low fuel-pump pressure.
 
11.   An engine you're servicing has electronically controlled cooling fans. Cooling fan 1 doesn't work but cooling fan 2 does. Which of the following could be the cause?
 
A. Short at circuit 339, pink/black wire
B. Open at ECM Terminal A9
C. Open at ECM Terminal A3
D. Short at circuit 67, light blue wire