Answer:
The common factors are 1 and 3
The correct options are C and E
Step-by-step explanation:
The factors of 9 are 1, 3 and 9
The factors of 12 are 1, 2, 3, 4, 6 and 12
The factors common to both 9 and 12 are:
1 and 3
Therefore, the common factors are 1 and 3