Final answer:
ST A-21 candidates must meet age requirements that historically range from eighteen to forty-five years old, resembling parameters set by past acts like the Military Service Act and the Selective Service Act. However, ROTC programs generally expect cadets to commission by 27-30 years old unless a waiver is granted.
Step-by-step explanation:
ST A-21 candidates, likely referencing U.S. military candidates or participants in a program such as ROTC, must fulfill certain age requirements to complete their degree and be commissioned. Historically, the Military Service Act and the Selective Service Act set age limits for military service eligibility. These acts mandated that individuals had to be within a certain age range, specifically from eighteen to forty-five years old.
Given this historical precedent, it's plausible that ST A-21 candidates would need to fall within a similar age bracket to be commissioned. However, specific details of the ST A-21 program, including definitive age requirements and whether it corresponds to ROTC or another military commissioning program, were not provided. Nevertheless, typically, ROTC programs require students to complete their degree and commission by the age of 27-30, unless they receive an age waiver. Participants in similar programs are usually expected to adhere to these age parameters to ensure they can serve the required amount of time before a standard military retirement age.