With no explanation, label text_A→text_B with either "not-entailed" or "entailed".
text_A: Although while in jail in the early 1980s , Zawahiri caused considerable tension by challenging the blind sheik 's ability to lead a coalition of the Egyptian Islamic Jihad and the Egyptian Islamic Group , Zawahiri and OBL are Rahman 's friends .
text_B: The causing happened
entailed.