The formula for finding the volume of a right rectangular prism is V = lwh, where l is the length, w is the width, and h is the height of the prism.
Since the volume given is 43.75 ft^3, we know that V = 43.75 ft^3.
To find the length, width, and height of the prism, we need more information. Without knowing the values of at least two out of the three dimensions, we cannot determine the volume using the formula.
Therefore, the correct answer is none of the options provided.