'area code for London' vs. 'area code of London'

[Stone]

English Error, Elementary Level

ESL/EFL Test #13 "Telephones", question 2

The area code for London for example is 207 if you call for within the UK.

(a) for
(b) for
(c) for

English Error, Elementary Level

ESL/EFL Test #13 "Telephones", answer 2

The area code for London for example is 207 if you call from within the UK.

Correct entry: from
The error was: (c) for

You have not found the error.
The area code of London for example is 207 if you call for within the UK.
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Dear Sir

why is "from" here

thanks a lot

Stone

[Alan]

Hi Stone,

You asked about from in this sentence:

The area code for London for example is 207 if you call from within the UK.

The idea behind of from is that it suggests out of. In other words you are in the UK and you dial out of the UK to London.

Alan
_________________
English as a Second Language
You can read my ESL story Present Simple

[Cath]

There's a more fundamental error with the question.

There is no such area code as 0207 or 0208.

The area code for London is 020. Local numbers have eight digits.

This change occurred nearly ten years ago. See also http://en.wikipedia.org/wiki/UK_telephone_code_misconceptions and http://en.wikipedia.org/wiki/020

[Cath]

Of course, having correct English is the main priority here, but shouldn't the questions and answers also be 100% factually accurate too?

[Cath]

Nearly three months later....

Please fix this!