Answer: C. 15
Answer: (C) 15
GSTIN is a 15-character alpha-numeric code: first 2 digits — state code; next 10 characters — PAN of the taxpayer; 13th character — entity number; 14th character — the letter Z (by default); 15th character — check code. \(2 + 10 + 1 + 1 + 1 = 15\).