Which of the Following Reasons Accounts for the Relative Ineffectiveness

Which of the following reasons accounts for the relative ineffectiveness of marijuana eradication strategies?

A) large quantities are generally grown in remote, largely inaccessible areas making eradication efforts time-consuming, labor-intensive, and dangerous
B) spraying crops with chemicals can be hazardous to people, water supplies, animals and other vegetation
C) the huge profits that can be made from a marijuana crop create a powerful incentive not to be deterred by eradication efforts
D) all of the choices are reasons