Please help with the following Questions - Auto-Mechanics (Part 4)

2.   Technician A says that many port fuel-injection systems on four-cylinder engines use a simultaneous firing of injectors. Technician B says that sequential fuel injectors are timed and pulsed individually, much like the spark plugs are sequentially operated in firing order of the engine. Who is correct?
     
A. Technician B
B. Both Technicians A and B
C. Neither Technician A nor B
D. Technician A

4.   Two technicians are discussing how to check fuel injector resistance. Technician A says that you would use a digital ohmmeter read in tenths of an ohm to measure the resistance across the injector terminals. Technician B says that the resistance of the injectors should be measured twice—once when the engine and injectors are cold and once after the engine has reached normal operating temperature. Who is correct?
     
A. Both Technicians A and B
B. Technician B
C. Neither Technician A nor B
D. Technician A
 
5.   After removing the vacuum hose from the fuel-pressure regulator, you see gasoline has dripped out of the hose. Technician A says that the fuel pressure regulator is defective. Technician B says that one or more of the injectors may be defective, causing the fuel to get into the hose. Who is correct?
     
A. Both Technicians A and B
B. Neither Technician A nor B
C. Technician A
D. Technician B

10.   Technician A says that the powertrain control module (PCM) uses the manifold absolute pressure (MAP) sensor to determine the load on the engine and the amount of fuel needed. Technician B says that, at idle, the MAP sensor voltage will be higher at high altitudes than when at sea level. Who is correct?
     
A. Technician B
B. Both Technicians A and B
C. Technician A
D. Neither Technician A nor B

12.   An oxygen sensor is being tested with a DMM using the min/max function. Technician A says that a good oxygen sensor should be able to produce a value of less than 100 mV and a maximum voltage above 900 mV. Technician B says that you should replace any oxygen sensor that fails to go above 700 mV or fails to go lower than 300 mV. Who is correct?
     
A. Both Technicians A and B
B. Technician B
C. Technician A
D. Neither Technician A nor B