Explanation:

- Let's first analyze the original set {12, 18, 6}:

- The numbers are all multiples of 6.

- The set consists of even numbers.

- Option 1: {18, 9, 8}

- Contains both even and odd numbers.

- Not all are multiples of a common number.

- Option 2: {9, 14, 11}

- All numbers are odd or even but not multiples of a certain number.

- Option 3: {16, 12, 8}

- All are even numbers.

- Each number differs from the next by 4.

- None are multiples of a common non-trivial number (other than 4), but similarity with all-even numbers is notable.

- Option 4: {15, 13, 11}

- All odd, all prime except 15.

- Not similar to the original set.

Correct Answer is Option 3: {16, 12, 8}