Explanation:

- The relationship between the first term (273) and the second term (21) can be found by adding the digits of 273 (2 + 7 + 3 = 12) and then multiplying by 3: 12 × 3 = 36. This does not give 21 directly, indicating further inspection might be needed.

- On trying another approach, the actual relationship uses subtraction and division: 273 divided by 13 equals 21.

- For the third term (221), applying a similar logic from the first relationship, 221 divided by 13 equals 17.

- The relationship between the fifth term (364) and the sixth term (28) follows the same pattern: 364 divided by 13 equals 28.

- Given these patterns, the correct option for the related term is Option 4, 17, as it fits the relationship consistently.

Correct Answer: Option 4 - 17

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