Hummmmm, I've tried to add a-i, and it picked up letters at the start of the sentences.

[\(0-9a-i]@[\(0-9a-i, \)]{1;}

Duis aute irure dolor reprehenderit in voluptate velit2)
Ut enim ad minim veniam, quis nostrud (a)
Ut enim ad minim veniam, quis nostrud(a), (b), (c)
Ut enim ad minim veniam, quis nostrud a), b), c)

without telling me the full solution, could you guide me as to what I need to look for?

Cendrinne