The restructuring agency
explored several alternatives, including complete and partial liquidation of assets, but has not found any feasible solution to the problems faced by the company.
Error Analysis:- Verb tense "explored" seems to be correct. Intended meaning is
Agency explored few alternatives but no feasible solution has been found.. I couldn't see any error in original sentence.
(A) explored several alternatives, including complete and partial liquidation of assets, but has not found
Correct.
(B) had explored several alternatives, which include complete and partial liquidation of assets, but has not found
Incorrect. Past perfect "had explored" isn't required.
(C) explored several alternatives, including complete and partial liquidation of assets, but did not found
Incorrect. "didn't found" is wrong usage. we would require "has found".
(D) has explored several alternatives, including complete and partial liquidation of assets, but has not found
Incorrect. "has explored" seems to be wrong because as per original sentence exploration is completed.
(E) has explored several alternatives, including complete and partial liquidation of assets, but did not find
Incorrect. "didn't find" is incorrect.
IMO A.