Which of the following types of amino acid modification involves the addition of a phosphate group?

A Acetylation
B Methylation
C Phosphorylation
D Ubiquitination
Phosphorylation is a type of post-translational modification that involves the addition of a phosphate group to an amino acid residue, often serine, threonine, or tyrosine.
Phosphorylation = 'phosphate' addition → adds a phosphate group
Nelson et al., Lehninger Principles of Biochemistry
Protein Metabolism Biochemistry Post-Translational Modification Easy MEDICAL Confidence: high