Question

The common factor of 3ab and 2cd is:

• A. 1
• B. -1
• C. a
• D. c

Answer 1

The correct option is A

1

1, 3, a, b, 3a, 3b, 3ab, ab are the factors of 3ab.
1, 2, c, d, 2d, 2c, 2cd, cd, are the factors of 2cd.
The two terms have 1 as a common factor.