so let's check 8 for example: 
step 1: (x^4 + 19^3 + 108x^2 + 236x + 176) - x^3(x-8) = 
27x^3 + 108x^2 + 236x +176 
step 2: (27x^3 + 108x^2 + 236x + 176) - 27x^2(x-8) = 
324x^2 + 236x + 176 
step 3: (324x^2 + 236x + 176 ) - 324x(x-8) = 2812x + 176 
step4: 2812x + 176 - 2812(x-8) = 2812*8 + 176 
which is not zero. 
actually you can see that all your answers A - D are incorrect, because the coefficients of the equation are all positive, so the if x is positive the value of the equation is also always positive. 
This equation can have only negative roots (if it has any)