请选择DCBA1Y;B/p*N.]5n+L5U.o;|What _____ useful dictionary it is!,\'K5V(_;a1i7O2I.q)z6|
A. a,\'K5V(_;a1i7O2I.q)z6|
B. an,\'K5V(_;a1i7O2I.q)z6|
C. the,\'K5V(_;a1i7O2I.q)z6|
D. /,\'K5V(_;a1i7O2I.q)z6|