One line has an answer of “C'est l'un des plus anciens lieux de culte du pays.”
and then also of “C'est un des plus anciens lieux de culte du pays.”
But the audio is “c’est l’un”, not “c’est un”, so I guess the second answer shouldn’t appear as an option, even if it’s a grammatically correct alternative.
Not a big issue, but I thought I’d mention it.