I do the following sequence of operations in MS Paint:

1. Draw an oval.
2. Draw a rectangle.
3. Fill the rectangle with red colour.

Then, I press Ctrl+Z two times.
What will be visible on the screen?

Answer: C. Only the oval

The sequence is

1. Draw an oval.
2. Draw a rectangle.
3. Fill the rectangle with red colour.

First Ctrl+Z removes the task done in step 3.
Second Ctrl+Z removes the task done in step 2.

So, only the oval remains on screen.

Answering after opening this box earns no Practice Points.