The area of the garden = \(x * y = xy\)
The area of the garden + walkway = \((x+4)(y+4)\); since the width of the walkway is 2 feet wide hence 2+2 = 4 feet will be added to length and width of the garden for a combined length and breadth as the garden is surrounded by walkway

the area of walkway = \((x+4)(y=4) - xy\)
simplifying the area of the garden + walkway = \(xy + 4x + 4y + 16\)
therefore, area of the walkway = \(xy + 4x + 4y + 16 - xy = 4x + 4y + 16\)
option D
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