The requirements in this subpart apply to the licensees and other entities identified in §26.3(a), (b), and, as applicable, (c) for the categories of individuals in §26.4(a) through (d), and, at the licensee's or other entity's discretion, in §26.4(g) and, if necessary, §26.4(j). The requirements in this subpart also apply to the licensees and other entities specified in §26.3(c), as applicable, for the categories of individuals in §26.4(e). At the discretion of a licensee or other entity in §26.3(c), the requirements of this subpart also may be applied to the categories of individuals identified in §26.4(f). In addition, the requirements in this subpart apply to the entities in §26.3(d) to the extent that a licensee or other entity relies on the C/V to meet the requirements of this subpart. Certain requirements in this subpart also apply to the individuals specified in §26.4(h).