から problem in Japanese For Everyone Lesson 5

[phreadom]

On exercise 12 in Lesson 5, I seem to understand all the questions except for #3

きょくばんは、東京だから（　　　）。

The given answer is "０３ですね。"

The other sentences all seem to have the meaning "because XXX, YYY"

Could someone explain this to me in a way that will help it "click" in my brain? おねがいします！

[blutorange]

"As for the telephone exchange number [some kind of prefix number]: Because it is Tokyo [we want to phone to], it [the number] is 03."

For other locations/area, we would use a different "telephone exchange number". Given this context, all makes sense : )

Edit: Taken from the 明鏡国語辞典

きょく-ばん　【局番】
《名》
電話番号の前につける、各電話局の呼び出し番号。
「市外局番」

[phreadom]

Thank you.

As I was looking over it again that general meaning occurred to me... "As for the area code, because it's Tokyo, it's 03 right?"

Now I can confidently move on to Lesson 6! ありがとうございます！