Q. 285 :

Even though the state has spent ten years and seven million dollars planning a reservoir along the Ubi River, the project will have to be abandoned as a result of the river becoming so heavily polluted.

(A) will have to be abandoned as a result of the river becoming so heavily polluted
(B) is to be abandoned on account of the heavy pollution which the river received
(C) had to be abandoned because the river had received such heavy pollution
(D) has to be abandoned because of the river and its heavy pollution
(E) must be abandoned because the river has become so heavily polluted


Could someone pls help understand why the OA is E here and not A.
Will be grateful.

Thanks and Regards,
Girish Malik