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
_________________

This is my response to the question and may be incorrect. Feel free to rectify any mistakes