Interfaces lack implementation; they must be supported by ...

[cherise1989]

Interfaces lack implementation; they must be supported by ________ classes.
 
  A) concrete
  B) abstract
  C) super
  D) multiple

Question 2

Why is user training such an important part of system development?
 
  What will be an ideal response?

[wshriver]

Answer to Question 1

A

Answer to Question 2

People use applications to perform tasks. These tasks are modeled through use cases and, therefore, use cases provide effective templates for user training. However, one kind of training is not enough; nor it can fit every situation. The exact nature of training depends on what the user is to be trained for, who the user is, and where the training is to take place.
The primary tool for training the user is the user interface its design, its flow, and the tools that it can exploit to help and guide the user. A wizard employs a user interface that guides the users, step-by-step, through simple forms or pages. However, it can be time-consuming and annoying to experienced users.