Given:
Diameter of a circular garden is, d = 10 yards.
The objective is to find the area of the garden.
The formula to find the circular area is,
[tex]A=\pi r^2[/tex]Radius of the circle is defined as the half of the diameter of the circle.
[tex]\begin{gathered} A=3.14\cdot\frac{10}{2}\cdot\frac{10}{2} \\ A=3.14\cdot5\cdot5 \\ A=78.5yd^2 \end{gathered}[/tex]Thus, the area of the garden is 78.5 square yards.
Hence, option (D) is the correct answer.