The correct answer is Commercial software that is sold ready for immediate use and this phrase defines COTS.

COTS refers to commercial software that customers can purchase and deploy without custom development. Vendors supply the product and provide updates and support and it is intended to be used immediately rather than built in house.

Security mechanisms that are simple to set up is incorrect because that choice describes ease of configuration for security features rather than the sourcing model of software. COTS is about acquiring ready made commercial products.

A managed cloud service offered by a third party is incorrect because that describes a hosted or managed service such as SaaS or a managed offering. Those focus on delivery and hosting rather than the purchase of a packaged commercial product.

Software created in house by a company for its own use is incorrect because that describes custom or in house developed software which is the opposite of commercial off the shelf products.

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