It is not the Mandarin Orange.
Remember that one of the clues was that the fruit is not eaten unless candied. Another clue also said it was not an orange. Any of those points would have excluded the Mandarin Orange.
I'm looking at a decently popular citrus fruit in the East, often used during Chinese New Year celebrations. It's called Citrus medica, fingered citron, or more commonly Buddha's hand.
Once you know it's a citrus fruit, asking about its shape next should still give you plenty of clues to deduct.