Laboratory tests on the urine of a patient identified the presence ofmethylmalonate (−OOC–CH(CH3)–COO−). Methylmalonate is bestdescribed as which one of the following A: A strong acid B: The conjugate base of a weak acid C: It is 100% dissociated at its pKa. D: It is 50% dissociated at the pH of the blood. E: It is a major intracellular buffer.