The question asks to identify the external sources of recruitment. Let's examine each option:
- Transfers: This is an internal source of recruitment as it involves reallocating existing employees within the organization.
- Campus Recruitment: This involves hiring fresh talent from educational institutions and is considered an external recruitment source.
- Advertisements: Job vacancies are publicized to attract candidates external to the organization, thus an external recruitment method.
- Web Publishing: Posting job openings on online platforms to attract external candidates also constitutes an external source.
Given these explanations, the external sources among the options provided are Campus Recruitment, Advertisements, and Web Publishing.
Therefore, the correct set of external sources is (B), (C), and (D) only.