An 83-year-old woman living at home with limited mobility wa…

An 83-year-old woman living at home with limited mobility was visited by paramedics following a 911 call by his neighbor. Physical exam revealed disorientation, muscle weakness, and a BMI of 15.4 kg/m2. History revealed malnutrition due to a diet consisting primarily of ramen noodle soup. Which of the following amino acids is most likely deficient in this patient?