Scholars Have Deduced the Likely Contents of the Q Document

Scholars have deduced the likely contents of the Q document by

A) isolating the teaching material that is contained in both Luke and Matthew but missing from Mark.
B) comparing the parables used in John to those used in Matthew,Mark,and Luke.
C) isolating the references to Jesus' Passion in Matthew and Luke and comparing them to Mark.
D) comparing the "cast of characters" which are contained in both Matthew and Mark but missing from Luke.