A. 9x+8
B. 18x
C. 18x+16
D. 9x

Step-by-step explanation:
Length = 5x +4
Breadth = 4x-4
Perimeter = 2(L+B)
Perimeter :
[tex]2(5x + 4 + (4x - 4)) \\ 2(5x + 4 + 4x - 4) \\ 2(5x + 4x + 4 - 4) \\ 2(9x) = 2 \times 9x[/tex]
[tex] = 18x[/tex]