Studies have shown that soils rich in zinc salts can enhance the productivity of crop plants. In addition, it has been demonstrated that use of a liquid fertilizer fortified with zinc enhances the productivity of citrus trees. A new study is prepared to examine the effects of zinc on the productivity of green pepper plants by using a fertilizer with a high zinc content called PHAT PLANT. Green pepper plants will also be grown with a fertilizer that has the same formulation as PHAT PLANT except that it has a low zinc content. Which of the following statements most accurately represents the question being asked in this study?
A) Does PHAT PLANT have an effect on the productivity of pepper plants?
B) Does zinc have an effect on the productivity of pepper plants?
C) Do zinc fertilizers have an effect on the productivity of pepper plants?
D) Does zinc-rich soil have an effect on the productivity of pepper plants?