I'm not sure about the first two but I think the one about the halite crystal is cubic. :)
Answer: I think the answer is A. because I remember doing it when we were still in school I chose A. and I got a 100%.
I would say
a. biological pest control
biological pest control is when other plants or animals are used to control pests. There are no chemicals used only the natural roles of the environment.
Hope this helped!