Answer : 2. "Albert Sabrin"
Explanation :

Dr. Albert Sabin, a physician and microbiologist, developed the oral polio vaccine (OPV). Sabin's vaccine was first used in 1961. 

OPV is a live attenuated (weakened) vaccine. 

 It's the main vaccine used to eradicate polio. 

 OPV is used in some countries, but not in the United States. In the US, the only polio vaccine given since 2000 is the inactivated polio vaccine (IPV). IPV is given as a shot in the arm or leg. 

Jonas Salk, an American physician, discovered the polio vaccine in the early 1950s