var correctchoices=new Array()
correctchoices[1]='d'
correctchoices[2]='b'
correctchoices[3]='c'
correctchoices[4]='a'
correctchoices[5]='d'
correctchoices[6]='c'
correctchoices[7]='b'
correctchoices[8]='b'
correctchoices[9]='c'
correctchoices[10]='d'
correctchoices[11]='d'
correctchoices[12]='b'
correctchoices[13]='c'
correctchoices[14]='a'
correctchoices[15]='d'
correctchoices[16]='c'
correctchoices[17]='c'
correctchoices[18]='b'
correctchoices[19]='c'
correctchoices[20]='b'