Outsourcing is the formal business practice of contracting with an external party to perform services or create goods that were traditionally handled internally. This strategic decision is often made to reduce costs, gain access to specialized skills, or allow the organization to focus on its core competencies. It is a fundamental concept in supply chain and contract management, representing the "buy" decision in a make-or-buy analysis. The term encompasses a wide range of activities, from manufacturing and IT services to customer support and logistics, making it the most accurate and commonly known term for the practice described.

A. External Rendering: This is not a standard or recognized term in business or contract management for the general practice of procuring external support.

C. Outdoor services: This term is too specific, referring to a narrow category of services like landscaping or facilities maintenance, not the broad concept in the question.

D. All of the above: This option is incorrect because options A and C are not the correct, universally accepted term for this practice.

1. National Contract Management Association. (2019). Contract Management Body of Knowledge (CMBOK) (6th ed.). Section 1.3.4, "Make-or-Buy Decisions." The decision to "buy" from an external source is the foundational step leading to outsourcing.

2. Lacity, M. C., & Willcocks, L. P. (2015). A new approach to automating services. MIT Sloan Management Review, 57(1), 13-16. This article discusses outsourcing as the established practice of obtaining services from outside an organization.

3. Handfield, R. B. (2006). A Brief History of Outsourcing. North Carolina State University, Supply Chain Resource Cooperative. Page 2 defines outsourcing as "the strategic use of outside resources to perform activities traditionally handled by internal staff and resources."