Answer: 2,3,4,-5
Explanation:
it seems that 40 is supposed to be 4c.
the terms can be grouped in several ways
2a, -5a Contain factor ‘a’
8, -4. Simple integers/constants
2a, 4c, 8, -4. Even numbers
2a, 3b, 4c, -5a Contain a factor
Can’t group on + or - because values of a,b,c are unknown
From the available choices, only 2,3,4,-5 matches a logical group.
