Critical Reasoning

Using a complex algorithm, a new computer program organizes email messages in a user's inbox, whether that inbox be part of an Internet email service or an email software package, by placing them in an order that is not necessarily chronological, but instead one that follows personal and specific preferences chosen by that user during the installation process. The free program has been painstakingly tested and its operation has proven to be faultless. Still, early users of the program, although giving it a fair chance by using it according to the recommended trial conditions, found the program to be impractical for their personal needs.

Which of the following, if true, would most contribute to an explanation of the facts above?

A. Even though the code of no two computer programs is developed in exactly the same way, most follow a general format that enables a programmer unfamiliar with a project to comprehend the functionality of a certain software item.
B. Software development companies spend time, energy, and money making their products as user-friendly as possible, but many fail by not introducing some form of personal flexibility to their programs.
C. Although in today's world most people have the ability to adapt to ever-changing software tools, it seems that there will always be an economic barrier reserving the use of advanced technology for those who can afford it.
D. The program's operation was first tested and debugged by the developers who, once satisfied, then sent it to be analyzed by an external quality control company that specializes in software development and evaluation.
E. Depending on the specific functionality of an individual program, having certain parameters that can only be adjusted or configured when the program is installed can have a negative influence on its overall performance.

What's the best approach to determine the answer? Can any experts help?