Z.x = y; x + y + z = 5z→ x + y = 4z.→ 2x = 4z; x = 2zthree years agox – 3 = 3 (z – 3)→ 2z – 3 = 3z – 9 (as x = y = 2z)→ 9 – 3 = z→ 6 = zPresent age of C is 6 years and after 4 years from now C will be 10 years old.Hence, 10 is the correct ANSWER.