An IS auditor determines that the vendor's deliverables do not include the source code for...

The correct answer is C. Software escrow agreement. A software escrow agreement is a legal arrangement between three parties: the software developer (licensor), the end-user (licensee), and an escrow agent. The agreement ensures that the software’s source code and other relevant assets are securely stored with the escrow agent, and can be released to the licensee under certain conditions, such as the licensor’s bankruptcy, insolvency, or failure to provide support or maintenance1. A software escrow agreement can provide the licensee with assurance and continuity for the software they depend on, and protect them from losing access or functionality in case of any unforeseen events or disputes with the licensor1.