Answer: TDMA(Time division multiple access)
Explanation: Time-division multiple access is the method that is used by GSM(Global system for mobile communication) usually for the separation process of the data.It is a way in which a same frequency is shared by different time slots of signal.It has high flexibility and so thus is helpful for the GSM network and provides easy services of division.It divides the data according to the time period slots in a GSM network.
The correct answer is A because they cant protect in real time
One gallon is 3.7854 liter so 4 liters are more than one gallon.
It could fail, it would take a long time setting it up and aslo it could be easily hacked.