The factors of 67 are 1 and 67. For them to be common, they need to be compared to another set of factors.
There are only two correct choices: 1 and 67.
The common factors of 18 and 36 are 18,9,6,3,2,1.
The common factors of 27 and 36 are 1, 3 and 9.
The common factors of 15 and 36 are: 1, 3.
The common factors of 36 and 40 are 1,2 and 4.
Since 67 and 40 have no common factors, the common denominator is simply 67 x 40.
Since 12 is a factor of 36, all of the factors of 12 are common to 36.
The common factors of 21 and 36 are 1 and 3
The common factors of 36 and 63 are 1, 3 and 9
The common factors of 36 and 80 are: 1, 2, and 4
Since 9 is a factor of 36, all of its factors are common.