【单选题】

Creating a relatively simple model of the known ecosystem requires a tremendous amount of work even with______set of data at our disposal; creating an accurate model for less well-understood ecosystems might well prove______pursuit.
A．(A) a comprehensive … a quixotic

B．(B) an expansive … a realistic
C．(C) a consequential … a viable
D．(D) an unproven … a feasible
E．(E) an incomplete … an impossible