Blacklist

A phone manufacturer is implementing a blacklist feature so that you can block certain numbers from reaching you.

Storing actual phone numbers in the blacklist takes too much memory, so it will save only the first two digits. When a call is received, it will check if the first two digit of the number presents in the blacklist or not. If so, it will reject the call.

Alice is using the phone and added some numbers into the blacklist. Which of the following scenario could happen?

A. Alice receives calls from a blacklisted number.
B. Alice couldn't receive calls from some whitelisted number.
C. None of the above, the blacklist feature works fine.

×

Problem Loading...

Note Loading...

Set Loading...