Explanation:

- To determine the HCF (highest common factor) of 69, 96, and 99, we need to find the greatest number that can divide all three of them.

- Break down each number into its prime factors:

- 69 = 3 × 23

- 96 = 25 × 3

- 99 = 3² × 11

- The common factor among all three numbers is 3.

- Therefore, the HCF of 69, 96, and 99 is 3.

- Option 1 - 3: Correct. The HCF is indeed 3.

- Option 2 - 9: Incorrect, as 9 is not a common factor.

- Option 3 - 1: Incorrect but possible if no common factors.

- Option 4 - 6: Incorrect, as 6 is not a factor of all.