This code uses the function open() which takes two parameters. The first parameter is the file name while the second parameter is the mode in which you are accessing the file.
The "r" mode opens the file in a reading state. That is, you can only read from the file. This code completes the reading process
aFile.read( )
The "w" mode opens the file so you can write to it and make changes.
The "a" mode opens the file so you can add contents to it.
I believe the correct answer is the first option. The primary difference between 3g and 4g cellular systems would be that 4g systems have faster transmission as compared to 3g. The G would mean generation. The very difference of both is their speeds.
