Once We Have Implemented a Solution, We Are Not Done

Multiple Choice

Once we have implemented a solution, we are not done with the problem because

A) the solution may not be the best (most efficient)
B) the solution may have errors and need testing and fixing
C) the solution may, at a later date, need revising to handle new specifications
D) the solution may, at a later date, need revising because of new programming language features
E) All of these