Answer: b 10
Explanation:
the prime factorization of 110: 2 * 5 * 11
the prime factorization of 40: 2^3 * 5
the prime factorization of 120: 2^3 * 3 * 5
the factor they all share is only 2, and they all share 5 but they dont all share 11 and 3. Multiply 2 * 5 = 10. SO 10 is the GCF (Greatest Common Factor) of 110, 40, and 120.
hope this helps!