Ans: D
Note that the slope of the straight line $4x+y-2=0$ is $-4$. Hence, the straight line with slope $\dfrac{1}{4}$ is perpendicular to the straight line $4x+y-2=0$. The slope of the straight line $x-4y+9=0$ is $\dfrac{1}{4}$. Hence, D is the answer.
Note that the slope of the straight line $4x+y-2=0$ is $-4$. Hence, the straight line with slope $\dfrac{1}{4}$ is perpendicular to the straight line $4x+y-2=0$. The slope of the straight line $x-4y+9=0$ is $\dfrac{1}{4}$. Hence, D is the answer.
