When more than one subunit join to form a larger protein, what is the final structure considered?

A) A primary sequence
B) A secondary structure
C) A tertiary structure
D) A quaternary structure

When multiple subunits come together to form a larger protein, the resulting structure is known as a quaternary structure. This level of structure involves the assembly of several protein molecules or polypeptide chains, typically called subunits, into a larger functional complex.