The hints say "she/that" for Illa but the accepted translation is "Those temples are in the forum"
"Those" is the plural of "that" - I didn't spot it consciously until until I learnt my fourth language, Italian. We were learning Questo, Questi, Questa, Questae when I thought, We don't have plurals like that in English...then "duh" yes we do for one vs. many: this -> these, that -> those. Latin does it all with endings (like Italian!)
Illa doesn't mean she. I don't know why they accept that. Illa could mean that (female) or those (things), but not she.
"Illa" is probably the most common way of saying "she", just as "ille" is easily the most common way of saying "he".
The hints should also say "those", since in this case ill- has to agree in the ending with the word it's modifying, and generally the plural of words that end in -um (like templum) is -a, so illa templa.
Well, maybe back then. These days, shopping malls have lots of empty space and it's not uncommon to see churches in them, at least where I live.