A system's application servers need to be patched. The requirements for maintenance work are as follows: ✑ System downti

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A system's application servers need to be patched. The requirements for maintenance work are as follows:
✑ System downtime is not allowed.
✑ The application server in use must be in the sane patch status.
✑ System performance must be maintained during patching work.
✑ Testing after patching must be done before the application server is in use.
✑ If any trouble occurs, recover the previous version in ten minutes.
Which of the following methodologies should be selected?

A. Rolling update
B. Patching directly
C. Blue-green deployment
D. Three staging environments