Which of the following is a mode of transmission for infectious diseases?

Direct contact is a recognized mode of transmission for infectious diseases because it involves the physical transfer of pathogens from an infected individual to a susceptible person through touch or other physical interactions. This mode of transmission can occur through activities such as shaking hands, sexual contact, or touching contaminated surfaces, leading to disease spread.

In contrast, telephonic communication and reading medical literature do not facilitate the transfer of infectious agents. These activities do not involve close proximity or the exchange of bodily fluids or surfaces where pathogens can survive and be transmitted. Sitting in waiting rooms might increase the risk of exposure if individuals are in close proximity to others who are ill, but it is not a direct mode of transmission like direct contact.