Answer:
The last one
Explanation:
First one is not punctuated correctly
Second is appositive
Third is appositive
Fourth is the only one that makes sense
Answer:
The answer is C, "Dr. Jonas Salk, a medical researcher from New York, developed the first effective polio vaccine."
Explanation:
The other answers are not punctuated correctly. The first one should have a comma after "piece", the third one should have a comma after "class", and the fourth one shouldn't have a comma at all.