To make the penguin dance in the background for the entire duration of the program, Mark should use a while loop. This type of loop will allow the penguin to keep dancing continuously as long as the program is running.
If the environment specifically supports an infinite loop structure (like a "forever loop"), that would also work, but the standard approach in many programming environments would simply be a while true:
structure.
So the best answer based on the options provided is while loop.