Final answer:
Most likely, the hygiene practice of the homeless client is influenced by a lack of clean water and sanitation facilities, coupled with crowded living conditions and societal stigma that impacts the access to hygiene resources.
Step-by-step explanation:
The factor most likely to influence the hygiene practice of the homeless client is the combination of inadequate water supply, inadequate sanitation measures, and crowded living conditions, which are often exacerbated by a lack of access to health care and low levels of education. These underlying determinants make it challenging for homeless individuals to maintain good hygiene practices.
Furthermore, the stigma surrounding homelessness can affect personal hygiene habits, as societal attitudes may hinder homeless individuals from accessing public facilities where they could practice hygiene. Economic conditions, both local and national, also play a significant role, as a lack of affordable housing can contribute to the incidences of homelessness, subsequently affecting an individual's ability to maintain personal hygiene.