While Assessing a 7-Month-Old Infant,the Nurse Makes a Loud Noise

While assessing a 7-month-old infant,the nurse makes a loud noise and notes the following response: abduction and flexion of arms and legs;fanning of fingers,and curling of index and thumb in C position followed by infant bringing in arms and legs to body.What does the nurse know about this response?

A) This could indicate brachial nerve palsy.
B) This is an expected startle response at this age.
C) This reflex should have disappeared between 1 and 4 months of age.
D) It is normal as long as movements are symmetric bilaterally.