<p>Can anyone explain why this question's correct answer is A?</p>
<p>The gong, believed to have originated in Western Asia, reached China in the sixth century, where it continues to be used for a wide range of purposes, {including as} a military signal, a rhythmic accompaniment for vocal performance, and a ritual instrument.</p>
<p>A. including as
B. which include
C. which includes
D. including
E. they include as</p>