Final answer:
The area of the triangle is 2.5 square yards.
Step-by-step explanation:
The formula for finding the area of a triangle is given by:
Area = 0.5 × base × height
Given that the base (a) is 1 yard and the height (c) is 5 yards, we can substitute these values into the formula:
Area = 0.5 × 1 yard × 5 yards = 2.5 square yards
Therefore, the answer is 2.5 square yards (option d).