The best choices are B. and D.
Answer A. would not be a good explanation for the power of Bronte's vision. Answer A. implies a narrow point-of-view, which would to account for Bronte's "continuing appeal" or her powerful vision.
Similarly, Answer C. would not be a good explanation for the power of Bronte's vision. A "narrow and constrained" vision is similar to the idea found in Answer A. A narrow point-of-view would only appear to a small group of people and would not support the argument that Bronte had either a powerful vision or continuing appeal.
On the other hand, Answer B. and Answer D. indicate reasons why Bronte has both continuing appeal and powerful vision. Her work discusses questions that apply to humans in general -- not just governesses. Furthermore, the novel contains a set of multifaceted characters, who are likely to appeal to all sorts of readers.
The answer is A: <em>Phonology</em>. In<em> Linguistics</em>, Phonology refers to the study of sounds in languages. Another meaning for Phonology is the <em>phonological</em> <em>system of a language</em>, describing how a sound functions. <em>Syntax</em> refers to how the words are arranged grammaticaly in a sentence. <em>Morphology</em> is the study of the form of words and phrases. It analyzes the parts and structure of words.
