Answer: D.

Explanation:
Given : The charge of painting = $2 per square yard
Let x be the total cost of painting the triangular wall .
The base of the triangular wall = 4 yards
The height of the triangular wall = 6 yards
We know that the area of the triangle =

Thus, the area of the triangular wall =

Now, the total cost of painting the triangular wall =

Hence, the total cost of painting the triangular wall
