Question about this usage of mono

Hi,

In a magazine I recently bought, the following was written:

[...]サンシャイン・西友店で販売していた「うなぎ長焼」については、グリーンピースが西友に種の確認をしたところ「ニホンウナギ」と回答があったものが、DNA検査の結果「アメリカウナギ」であったことも判明。

is the mono in 回答があったものが the kind of mono you'd use in これは美味しいものだ, or would it be 〜だったものの〜? (in which case you could just have said だったが, no?)

Could the mono just be translated as "the one", as in "upon confirming the kind of unagi with Seiyu, the one that was labeled as Japanese unagi turned out to be American unagi" ?

Thanks!

Hi,

I'm sorry for my clumsy English.

I think the mono in 回答があったもの is the kind of mono I'd use in これは美味しいものだ.

in short, うなぎ長焼き one of the Japanese fish fish dish is miss-labeled Japanese unagi to American unagi.

in other words, 西友 told a lie that the unagi is Japanese unagi to グリーンピース.

Hi, and thank you for answering.

So it's indeed the "physical" thing, which would then mean my translation was correct. Great.

roundabout expression. ambiguous.
it is hard to decide whether the word(が) in the word(あったものが) is "格助詞" or "接続助詞".

格助詞
Unagi, which was answered as Japanese Unagi, turned out to be American unagi.

接続助詞
Unagi, which was sold in Sunshine Seiyu, turned out to be American unagi.