The correct option is C 40
Multiples of 2 are 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 44...
Multiples of 5 are 5, 10, 15, 20, 25, 30, 35, 40, ...
Multiples of 4 are 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, ...
So, the smallest common multiple of 2, 5, and 4 is 20
and the second smallest common multiple of 2, 5, and 4 is 40.