Which of these actions is most appropriate to perform on a 9-month-old infant at a well-child checkup?

A) Testing for Ortolani sign
B) Blood pressure measurement
C) Assessment for stereognosis
D) Assessment for the presence of the startle reflex

Stereognosis

The ability to perceive and recognize the form of an object by touch without visual and auditory information.

Ortolani Sign

A clinical sign used in the diagnosis of hip dysplasia in infants, involving a characteristic clicking sound during movement of the hip.

Startle Reflex

An involuntary movement in response to a sudden unexpected stimulus, commonly seen in infants as a quick jerking of the limbs.