Final answer:
The dimensions of the rectangular garden are Length: 28 and Width: 13.
Step-by-step explanation:
The dimensions of a rectangular garden can be represented by the factors of a polynomial expression. In this case, the factors are given as 28 and 13. So, the length of the garden is 28 units and the width is 13 units.
Therefore, the correct answer is a) Length: 28, Width: 13.