you must put the values in the quotes.
try this :
$query_add="INSERT INTO answer (`AnswerValue`,`AnswerKey` ,`Question`)
VALUES ('".$data[0]."','".$data[1]."','".$data[2]."')";
and when I try your code, with my changes above,this is the result :
3
3 fields in line :
INSERT INTO answer (`AnswerValue`,`AnswerKey` ,`Question`)
VALUES ('Respondent Name','name','1')