Final answer:
If alternative behaviors are not used to replace a problem behavior, the behavior is likely to become more intense and persistent as the individual's unaddressed needs drive them to continue seeking a desired outcome.
Step-by-step explanation:
If functionally equivalent alternative behaviors are not used to replace a problem behavior, it is likely that the problem behavior will intensify and become more persistent (Option A). This occurs because the underlying need or desire that is driving the problem behavior remains unaddressed. In the absence of a suitable and acceptable alternative to fulfill that need, the individual may increase the intensity or frequency of the problem behavior in an attempt to achieve the desired outcome. Without intervention, problem behaviors typically do not decrease spontaneously over time, nor do they change format without a reason, and external factors alone are generally insufficient to produce a lasting change in behavior.