There are 120 choices.
5 × 4 × 3 × 2×1 = 120 choices
The area equation is

, which when solved equals 50.24. That's the third answer on your list.
If you look at the graph of y = floor(x), you'll see a stairstep pattern that climbs up as you read from left to right. There are no vertical components to the graph. There are only horizontal components.
The graph is not periodic because the y values do not repeat themselves after a certain x value is passed. For instance, start at x = 0 and go to x = 3. You'll see the y values dont repeat themselves as if a sine function would. If you wanted the function to be periodic, the steps would have to go downhill at some point; however, this does not happen.
Conclusion: The function floor(x) is <u>not</u> periodic.
0.600. If I'm wrong please tell me so I can correct my answer and recalculate it.