rarity, raring...

5 лет назад

Hello, guys!
I hope you're all doing great today!

Which one is correct in 36? 
 36 a rarity b rare c rarely d raring
  "The container was opened by Liz Barham, the  Museum of London's conservator. She said: "It seems to be an ointment and it  has finger marks in the lid. If this is a sealed Roman container, those are  Roman finger marks. This find is a real (36) ........... . To find finger marks is  very extraordinary - we (37) ........... literally hands with history." 36 a rarity b rare c rarely d raring 
Since I see an article a I think a noun should be used. rare is an adjective meaning not seen or found very often rarely is an adverb meaning not often As for the rest it sounds like 'rarity' should work, but I don't remember hearing this word ever in my life. 