To prevent fecal-to-oral transmission of pathogenic microorganisms, it is important to

Wash hands after using the washroom.

Explanation:

Fecal oral transmission also known as oral fecal route, this transmission is defined as the route of the disease where pathogens which are present in fecal particles passes from person to the mouth.

Some common example of fecal oral transmission are fluids, fingers, flies, and food. Main cause of this transmission are poor hygiene practices, and lack of adequate sanitation.

the correct answer is d