Which of the Following Experiments Is the Best Way to Determine

Which of the following experiments is the best way to determine if an element is essential for plant growth?

A) Measure the amount of the element stored in plant tissues.
B) Grow plants in soil deficient in the element and note whether or not the plants are healthy.
C) Measure the amount of the element in the soil after plant growth.
D) Grow plants using hydroponics with and without the element and measure plant growth and health.
E) Measure the weight of the plant and soil before and after plant growth.