GCF is defined as the Greatest Common Factor. It is the greatest factor that divides two numbers. In order to find the GCF between the 2 numbers given, we need to find their prime factors first. If you have listed it already, the two common numbers are 2 and 5. So, multiply 2 by 5 and we get 10.
Therefore, the correct answer for this would be the last option, 10. Hope this answer helps.