This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Primary prevention-a) Marriage counselingb) Early diagnosis and treatmentc) Pap smeard) Self breast examinatione) Immunization 
Select and explain. 
A. da, B. ae, C. dea, D. ac
B: ae
Answer: B: ae 
Explanation: Immunization and marriage counseling (a type of health education) are primary level of prevention.
Pap smear is a screening test for cervical cancer and self breast examination is a screening test for breast lump both are secondary level of prevention.
Early diagnosis and treatment is a secondary level of prevention.