The variable x represent the width of the border. Option A is correct.
The space filled by a flat form or the surface of an item is known as the area.
The number of unit squares that cover the surface of a closed-form is the figure's area. Square centimeters is the unit of the area.
The total area of the place mat to include the border is represented by the expression;
(4+2x)(6+2x).
Total area = Surface area+inner area
Hence, option A is correct. The variable x represent the width of the border.
To learn more about the area, refer to the link;
https://brainly.com/question/11952845
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