Why should a person that takes an hiv test today also take one in 3 months?
a. so treatment can be more targeted and more effective
b. because antibodies may not be present until that point
c. to confirm the results from the first test
d. to see if any new sexual partners may have the disease

b. because antibodies may not be present until that point.

Explanation:

The length of time between the contraction of HIV and when the antibodies are detectable can go between 3–12 weeks. So even though a test can come negative today it can still be positive in three months. For safety and medical reasons it is necessary that people take two tests with a three month difference.