Should 「だ」 be used or not?


I'd like to know if 「だ」(or maybe even 「です」, though I somehow doubt it)
should/shouldn't or can/cannot be used in a sentence I met in one textbook.
The phrase was:

>   * 東京大学は日本で一番大きい大学と言われている。
>

that translates into something like "They say Todai is the biggest university
in Japan", no problems here. But by some reason I feel like the phrase lacks
「だ」 between 「大学」 and 「と」, so it would look like:

>   * 東京大学は日本で一番大きい大学 **だ** と言われている。
>

Am I right or not? Or maybe both variations are possible? Is there any
difference? Is the variant with 「です」 possible (I think not, but still... would
like to be confident)? Thanks!




I think in cases like [noun]+と言われてる the ”だ” before the と is optional, however
to me including it sounds a little more natural and complete.

However, saying ”〜大学 **です** と言われてる" would be pretty awkward in this type of
context, regardless of whether you were speaking polite language (と言われています) or
not.

です could be used in a case where you want to emphasize someone used polite
language when you directly are quoting them, i.e.

[code]

    お店に入ったら「今日はお休みです」と言われました。
    
[/code]

In the original sentence, the part before the と isn't really a direct quote
from anyone. It's like saying in English "This school is said to be very
expensive", where no one person specifically said that phrase.

