Which of the following would be the most effective strategy to ...

[Hungry!]

Which of the following would be the most effective strategy to remove toxic heavy metals from a soil?
A) heavy irrigation to leach out the heavy metals
B) application of fertilizers to compete with heavy metal uptake
C) application of sulfur to lower the soil pH and precipitate the heavy metals
D) adding plant species that have the ability to take up and volatilize heavy metals
E) inoculating soil with mycorrhizae to avoid heavy metal uptake

[clippers!]

I know it's D,

Have a wonderful day