Re: Question for those in the UK
My answer is basically the same as Amphelise's:
Today, I would say Caroline with the "eye" sound (Care-oh-line to rhyme with mine) and Maria ending with "ee-ah".
However, I've seen enough Regency dramas to know that pre-1850 or so, Maria would have ended with "eye-ah". Similar to how you would say Mariah Carey's name.
I've heard modern people of an older generation even say Sophia to rhyme with Mariah (i.e. Soph-eye-ah).