Which correctly uses or omits commas?

My sister Cecelia is always much more cheerful than my other sisters.

My sister Cecelia, is always much more cheerful than my other sisters.

My sister, Cecelia, is always much more cheerful than my other sisters.

My sister, Cecelia is always much more cheerful than my other sisters.

Question

Which correctly uses or omits commas? 



My sister Cecelia is always much more cheerful than my other sisters. 



My sister Cecelia, is always much more cheerful than my other sisters. 



My sister, Cecelia, is always much more cheerful than my other sisters. 



My sister, Cecelia is always much more cheerful than my other sisters.

anonymous · Answer

My sister, Cecelia,...
"Cecelia" is an appositive renaming "sister".