Tense

In the last hundred years, Alexandria … Egypt’s gateway to the outside world.
Its position made it the centre of commerce between East and West.

(a) was
(b) had been
(c) has been

  I am sitting on the fence between (b) and (c).
  Could anybody help me?

If it means 100 years ago until now, you would say: has been. If the period was 100 years ago until a time in the past (which is suggested by the use of ‘made’), you would say: had been.

Dear ALAN!Taking the criterion of the test (i.e. only one anwer is possible) into account, then which version would be correct in this case?
Thanks in advance…

Alan,
I believe the following past-perfect version is correct.
"In the last hundred years, Alexandria had been Egypt’s gateway to the outside world. "
In that case, when we are using ‘past-perfect tense’, there should be two events
(ie) one should be distant past event and the other must be recent past.
Does this sentence satisfy that norms?
Please elaborate and comment.

Alan,
Could you please help me?

Alan, which one is correct?

The use of the present perfect covers from then to now - the Dobsons have owned this house since i955 and they still live there
The use of the past perfect covers from then to another time before now - The Dobsons had owned the house from 1930 until 1955 before the Smith family bought the house in 1956.

The difference is as I have explained at 2 above.

Dear ALAN! Finally, in the test there are two equally correct answers, aren’t there?

It isn’t clear. You could in fact use all three!

You mean including “was” in (a)?

Yes.

with “in the last hundred years” we should use perfect tenses, shouldn’t we?

with “in the last hundred years” we should use ONLY perfect tenses, shouldn’t we?

I am quite confused now. In Alan’s explanation, I can understand why b) and c) are the correct choice. But in the sentence like that (no further context), I think present perfect tense will be a good choice.
Alan said a) can be correct too ? it made me confused. It is “In the last hundred years” (not “a hundred years ago”) , I wonder why a) could be a correct choice ?
Alan, May you explain me a bit about it ?