With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Clark Gable was an extra in silent films in the 1920's.
text_B: Collier City may refer to  :. Collier City , Broward County , Florida , a neighborhood in Pompano Beach. Collier City , Collier County , Florida , a former town on Marco Island. sometimes pronounced or referred to as `` Khia City ''
not_related.