The passage suggests that the factor mentioned in lines 19 — 23 complicates professors attempts to construct introductory reading lists for courses in Asian American studies in which of the following ways？

A. By making it difficult for professors to identify primary source material and to obtain standard information on Asian American history and culture.
By preventing professors from identifying excellent anthologies and introductory texts in the field that are both recent and understandable to students.
C. By preventing professors from adequately evaluating the quality of the numerous texts currently being published in the field.
D. Such courses were offered only at schools whose libraries were rich in primary sources.
E. By making it more necessary for professors to select readings for their courses that are not too challenging for students unfamiliar with Asian American history and culture.