Communicative intent appears months before children develop the motor

Communicative intent appears months before children develop the motor mechanisms required for speech, and scientists have conducted research into the physical gestures that function as a child's primary form of communication for a portion of its infancy.


A) the physical gestures that function as a child's primary form of communication for a portion of its infancy
B) the physical gestures that function for a child's primary form of communication in a portion of its infancy
C) physical gestures which function as a child's primary forms of communication for a portion of its infancy
D) the physical gestures which function as the primary form of communication of children during a portion of its infancy
E) a child's primary form of communication, physical gestures which become their primary form of communication during a portion of their infancy

function for vs function as :-
function as a -> Correct idiom
Eliminate B

physical gestures vs the physical gestures :-
we are talking about specific physical gestures hence the physical gestures should be correct
Eliminate C

children (plural) and its (singular) in D and which become their primary form are SV disagreement
Eliminate D and E


Therefore Answer - A