Which additional testing methods should the developers employ to prevent an outage?

Dress4win has end to end tests covering 100% of their endpoints.

They want to ensure that the move of cloud does not introduce any new bugs.

Which additional testing methods should the developers employ to prevent an outage?
A . They should run the end to end tests in the cloud staging environment to determine if the code is working as intended.
B . They should enable google stack driver debugger on the application code to show errors in the code
C . They should add additional unit tests and production scale load tests on their cloud staging environment.
D . They should add canary tests so developers can measure how much of an impact the new release causes to latency

Answer: B