While dwars and cretinism suffering child are somewhat of the same height, the main difference is that

The correct option is B

Cretins are mentally retarded

The correct option is B:

Explanation of the correct option:

1. The deficiency of growth hormone causes dwarfism.
2. The deficiency of thyroid hormones causes cretinism.
3. Dwarfism leads to short height and cretinism leads to retarded physical and mental development.

Explanation of the incorrect option:

Option A:

Cretins are mentally deranged

Option C:

The head of the cretin is normal size.

Option D:

The dwarfs do not have an elevated chin

Final answer: cretins are mentally retarded