This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable Diseases, Subject name: Social & Preventive Medicine
All the following statements regarding transmission of HIV are true EXCEPT: 
Select and explain. 
A. Circumscission will decrease the frequency of transmission, B. Associated STD's will not influence the transmission, C. Heterosexual contact is the most common route of transmission of HIV, D. Even after vigorous screening, HIV transmission can occur through blood transfusion
B: Associated STD's will not influence the transmission
Answer: B: Associated STD's will not influence the transmission 
Explanation: Ans) b (Associated STD's will not influence the transmission)Ref Park 20th edp 301"The size of the risk is affected by a number of factors, including the presence of STD, the sex and age of uninfected partner, the type of sexual act, the stage of illness of the uninfected partner and the virulence of the HIV strain"So associated presence of STDs will influence the rate of transmission of HIV.A11 other options are true regarding HIV.