C: "A small family is one with parents and a maximum of two children." - This introduces the definition of a small family.
A: "It is also called a nuclear family." - This follows naturally as it provides an alternate term for the concept introduced in the first sentence.
D: "The advantages of a small family are numerous." - This shifts the focus to the benefits of a small family.
B: "It is good to be in a small family because there is better management of resources." - This elaborates on one of the advantages mentioned in the previous sentence.
Thus, the sequence CADB forms a meaningful and coherent paragraph.