She upset Carlo at Christmas (5)

I believe the answer is:

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'she' is the definition.
(woman's name)

'upset carlo at christmas' is the wordplay.
'carlo' can be anagrammed to 'CAROL'.
But, I'm not clear how the anagram is indicated.

Can you help me to learn more?

(Other definitions for carol that I've seen before include "Coral (anag.)" , "Joyful religious song" , "Joyful song - girl's name" , "Girl" , "Song, especially at Christmas" .)

I've seen this clue in the Evening Standard.

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