Six Months into Development, the Core Team Assigned to Implement

Six months into development, the core team assigned to implement a new internal piece of software must convene to discuss a new requirement with the stake holders. A stakeholder identified a missing feature critical to the organization, which must be implemented. The team needs to validate the feasibility of the newly introduced requirement and ensure it does not introduce new vulnerabilities to the software and other applications that will integrate with it. Which of the following BEST describes what the company?

A) The system integration phase of the SDLC
B) The system analysis phase of SSDSLC
C) The system design phase of the SDLC
D) The system development phase of the SDLC