Which one of the following is the most efficient packing arrangement?

Which of the following is the most efficient in removing a proton from methanol ?

Which of the following metals make the most efficient catalyst

Which one of the following is a most efficient device to eliminate particular matters from the industrial emissions?

Which of the following will provide the most efficient overlap?

Which of the following represents the closet packed arrangement of uniform solid spheres:

In which pair most efficient packing is present?