A 12-year-old boy is diagnosed with Type 1 Diabetes Mellitus. Which of the following is the first-line lifelong therapy?

Correct option is C

Type 1 DM is due to autoimmune destruction of β-cells → absolute insulin deficiency. Only lifelong insulin therapy is effective.
Explanation of options: (a) ✘ Oral drugs are used in Type 2 DM, not Type 1. (b) ✘ Diet helps but cannot replace insulin. (c) ✔ Correct; insulin is mandatory for survival in T1DM. (d) ✘ Bariatric surgery helps in obese T2DM, not T1DM.