People that regularly wash their hands properly and effectively have a lower overall risk of contracting an infectious disease. Which of the following statements is/are reasons for this observation?

A. Many infectious diseases can be spread by asymptomatic carriers or people that are in the incubation/prodromal/convalescence phases of infection and therefore do not appear sick - regular hand hygiene would protect better than hand hygiene only when interacting with "sick" people because of this fact
B. Hand hygiene procedures, especially hand washing, are 100% effective at removing or killing infectious agents that are on the skin - This is why clinicians have to either wash their hands or use hand sanitizer both before and after interacting with a patient that has an infectious disease
C. The hands often interact with various portals of entry (mouth, nose, eyes, etc.) so any infectious agent that is present on the hands has the opportunity to enter the body and cause infection - Hand washing and other hand hygiene procedure reduce the number of infectious agents on the hands so the risk is lower that a pathogen would enter the body while eating, putting in contacts, etc.
d. All the above
e. A and C