What Is the Difference Between the Implementation Phase and the Maintenance

What is the difference between the implementation phase and the maintenance phase?

A) The implementation phase creates the physical design (code) and tests it;the maintenance phase places it into operations.
B) The implementation phase monitors new systems to ensure that they are working properly;the maintenance phase makes minor adjustments when needed to meet existing business goals.
C) The maintenance phase monitors new systems to ensure that they are working properly;the implementation phase makes minor adjustments when needed to meet new business goals.
D) The maintenance phase monitors and adjusts new and existing systems;the implementation phase places new systems into operation.