Which of the following is not a method for addressing soil contamination?

a.

excavate and dispose of the soil.

b.

use microbes to digest the contaminants.

c.

use heat to force the contaminants into the gas phase and out of the soil.

d.

none of the above

The methods given in the options "a", "b" and "c" are all useless methods and are never used. The correct option among all the options that are given in the question is the last option or option "d". The first option is not used as disposing of the soil is not a solution and a huge field of soil cannot be heated as is said in option "c". The second option of adding microbes is also not accurate.

The correct answer is D