The correct order from smallest to largest would be:
H < C < N < O < Amino acid < Globular Structure < Amino acid sequence
The smallest should begin from the basic elements. Among C, H, O and N, the lightest is Hydrogen, followed by Carbon, Nitrogen, and Oxygen. Next is the amino acid which is the most basic unit of protein. This is the linear structure. Followed by the globular structure which is the tertiary structure. The whole would be the amino acid sequence which is quaternary structure.