In HIV window period indicates:

Ans. is 'b' i.e., Time period between infection and detection of antibodies against HIV(Ref: Ananthanarayan, 9th/e, p. 579 and 8th/e, p. 578)* It takes 2 - 8 weeks to months for antibodies to appear after infection. This period, from infection to appearance of antibodies is called as window period.* During this period patients is seronegative, i.e., serological tests (ELISA and Western blot) are negative.* The individual may be highly infectious during this period.