The correct option is D 4
To determine the largest possible number of cartons needed we have to find out the greatest common factor of number 12, 16, 32
Factors of 12 = 1, 2, 3, 4, 6, 12
Factors of 16 = 1, 2, 4, 8, 16
Factors of 32 = 1, 2, 4, 8, 16, 32
We can see that 4 is the greatest common factor.
Hence, the largest possible number of cartoons needed = 4