Let me ask a question

Let say, you wanted to meet up a friend but somehow you can't get her through her mobile phone. She is in her office and you are just downstairs of the office. So, you get the office number and you called up.

ring ring ring~~~

unknown : hello~
you : hello, can i speak to xxx?
unknown : yes... Where are u calling from?
you : I'm.....

So... what's your answer??