The correct answer is (A) Flipping a selection converts it into a floating selection.

In LibreOffice Calc:

• (B) Flip Horizontal flips the left side to the right side is true.
• (C) Flip Horizontal flips the right side to the left side is true.
• (D) Flip Vertical flips the top to the bottom is true.

However, (A) Flipping a selection converts it into a floating selection is not true. Flipping an object does not change its selection type or make it floating; it only changes the orientation of the selection (horizontal or vertical flip).