as we know cycling of phosphorus ensures the supply of this element, this way living organisms have access to it, as is essential to all organisms, even more, is essential for animal growth, the Phosphorus has more functions than any other element its part of RNA and DNA, important for energy storage and sugar processing among other functions. Now it's important as often is a limiting resource in the environment and organisms compete for it also if the balance is lost it can carry severe ecological consequences, like eutrophication of lakes. Therefore taking this into account we can say that the correct answer is option b.