The correct answer is C. 大小和位置 (Size and Position).
The turtle.setup() function in Python's turtle graphics module is used to set both the size and the position of the main window. Here's a brief explanation:
For example, a typical usage might look like this:
turtle.setup(width=800, height=600, startx=0, starty=0)
This would create a window that is 800 pixels wide and 600 pixels high, positioned at the top-left corner of the screen.
It's worth noting that while the setup() function doesn't directly set the background color (which is option D), you can set the background color using other turtle methods like turtle.bgcolor().