Which of the Following Best Defines Proteins

Which of the following best defines proteins?

A) They are polyhydroxy aldehydes or ketones with the general formula C_n(H₂O) _m.
B) They are linear polymers of nucleotides that form the basic structural components of DNA and RNA.
C) They are organometallic compounds that have stabilized carbanions, whose general formula is RMgX, where X is Cl, Br, or I.
D) They are a family of compounds that include fats and waxes, characterized by their insolubility in water.
E) They are biological polymers with more than 50 amino acid residues linked together by amide bonds.