The following are some importance of marketing seedlings. Which among the choices are correct?
I. to ensure the physical condition of seedlings
II. to preserve the quality of seedlings
III. to decrease the number of plant species
IV. a way of increasing the production of trees and fruit-bearing trees

a.
I, II, III

b.
I, III, IV

c.
I, II, IV

d.
II, III, IV