Final answer:
New Mexico and Louisiana are the pair of states that now allows psychologists to legally prescribe drugs to their clients.
Step-by-step explanation:
A: The pair of states that now allows psychologists to legally prescribe drugs to their clients is New Mexico and Louisiana. In these states, psychologists are required to receive specialized training and meet specific criteria to obtain prescribing privileges. This change was introduced to help improve access to mental health care by allowing psychologists to provide a wider range of treatment options.