Transmission of HIV-Infection occurs by-

(A). Using infected needles by the health staff or by drug abusers
(B). Transfusion of contaminated blood and blood product
(C). Sexual contact with infected person
(D). Sharing food and sanitation facilities

Choose the correct answer from the options given below.

(A), (B) and (C) only

The correct answer is Option (2) → (A), (B) and (C) only 

The word AIDS stands for Acquired Immuno Deficiency Syndrome. This means deficiency of immune system, acquired during the lifetime of an individual indicating that it is not a congenital disease. ‘Syndrome’ means a group of symptoms.
AIDS was first reported in 1981 and in the last twenty-five years or so, it has spread all over the world killing more than 25 million persons. AIDS is caused by the Human Immuno deficiency Virus (HIV), a member of a group of viruses called retrovirus, which have an envelope enclosing the RNA genome. Transmission of HIV-infection generally occurs by :

(a) sexual contact with infected person,

(b) by transfusion of contaminated blood and blood products,

(c) by sharing infected needles as in the case of intravenous drug abusers 

(d) from infected mother to her child through placenta.

So, people who are at high risk of getting this infection includes - individuals who have multiple sexual partners, drug addicts who take drugs intravenously, individuals who require repeated blood transfusions and children born to an HIV infected mother.