Explanation:

In Bootstrap, to create an animated progress bar, you generally need to use .progress-bar-animated class. However, none of the options listed specifically create an animated progress bar.

Here’s a brief explanation of each option:

• (A) .active: This class is typically used for indicating active states for elements like list items or buttons, but not for animated progress bars.
• (B) .progress-success: This class is used to style a progress bar to indicate a "success" state, but it does not animate the progress bar.
• (C) .progress-active: There is no .progress-active class in Bootstrap for progress bars.

To create an animated progress bar in Bootstrap, you would use the class .progress-bar-animated, along with the standard progress bar classes. For example:

<div class="progress">

  <div class="progress-bar progress-bar-animated" style="width: 50%"></div>

</div>

This makes (D) None of the above the correct answer.