Final answer:
A Pap smear is the primary preventive measure young adult women should practice to detect and treat pre-cancerous cells early and reduce the risk of developing cervical cancer.
Step-by-step explanation:
The primary preventive measure that young adult women should practice is c) Pap smear. A Pap smear samples cells from the cervix to detect abnormal or pre-cancerous cells early, which can then be treated before they develop into cervical cancer. The prevalence of cervical cancer in the United States is very low, largely thanks to regular Pap smear screenings, proving the effectiveness of this preventive measure. Although Pap smears can be uncomfortable, and sometimes slightly painful, they are brief procedures that have a tremendous benefit in reducing up to 80 percent of cervical cancer deaths.