16.This article examines the properties and functions of cohesion and coherence in composition. The author points out the important role the reader’s _______ play in making a text coherent. In order to highlight the role of our background knowledge and our ability to reason and assume being the essential elements which make a text coherent, the author introduces a poem to clear the _______ water.
(A) schemas; foggy
(B) schema; dirty
(C) scheme; unclean
(D) schemata; muddy