What are simian creases?

Correct option is B

Simian crease refers to a single transverse palmar crease that extends across the entire palm. It is a congenital feature and can be seen in some healthy individuals, but is more commonly associated with genetic conditions like Down syndrome. It results from the fusion of the two typical palmar creases (head and heart lines).
Explanation of options: (a) ✘ Transverse ridge in nails – Not related to simian creases; may indicate systemic issues but not a palmar sign. (b) ✔ Single transverse palmar creases – Classic simian crease seen in genetic syndromes like Down syndrome. (c) ✘ Toe creases – These are unrelated and not characteristic of simian features. (d) ✘ Scalp creases – These are not standard diagnostic indicators and are unrelated to the term "simian crease."