Which course of action do you recommend?

A company must honor a service-level agreement (SLA) for its application, which states all
database requests must execute within three seconds.
Users complain that some requests take longer than five seconds to complete. You have been
contracted to fix the problem.
Which course of action do you recommend?

A.
Modify the program to implement multi threading and an event-driven design.

B.
Add servers to distribute the load.

C.
Upgrade the application server and the operating system.

D.
Define a plan for isolating the bottleneck, and define indicators that will measure performance
under a test load.