What is a common method by which HIV is transmitted?

HIV is primarily transmitted through sexual contact, making it the common method among the options presented. This includes vaginal, anal, and oral sex where bodily fluids such as semen, vaginal secretions, or blood can carry the virus. The virus must enter the bloodstream of an uninfected person, which can happen through mucous membranes found in the genital and rectal areas, as well as less commonly in the mouth.

The other methods listed are not recognized as pathways for HIV transmission. For instance, water is not a medium through which HIV can survive or be transmitted; the virus does not live long outside the human body. Sharing food does not spread HIV, as it is not transmitted through casual contact or sharing utensils. Aerosol droplets are also not a transmission route for HIV, as the virus is not airborne; it cannot be spread through sneezing or coughing. Thus, sexual contact remains the key and most significant route for the transmission of HIV.