Explanation

To find the largest number (HCF) that divides 12, 6, 3, and 24.

Factors of 12: 1, 2, 3, 4, 6, 12

Factors of 6: 1, 2, 3, 6

Factors of 3: 1, 3

Factors of 24: 1, 2, 3, 4, 6, 8, 12, 24

Therefore, the largest number (HCF) that divides 12, 6, 3, and 24 is 3.

The correct answer is: 3