which sentence is written correctly?\nkarina, the new student body president, was previously the class…

which sentence is written correctly?\nkarina, the new student body president, was previously the class treasurer.\nkarina the new student body president, was previously the class treasurer.\nkarina, the new student body president was previously the class treasurer.\nkarina the new student body president was previously the class treasurer.
Answer
Brief Explanations:
The appositive "the new student body president" should be set off by commas. It provides extra - identifying information about Karina and is non - essential to the basic meaning of the sentence.
Answer:
Karina, the new student body president, was previously the class treasurer.