The correct option is A 5
To find the number of groups, we need to find the number of factors that are in common between 20 and 30.
Factors of 20: 1, 2, 4, 5, 10, and 20
Factors of 30: 1, 2, 3, 5, 6, 10, 15, and 30
Common factors are 1, 2, 4, 5 and 10
Count = 5
∴ Total number of groups = 5