Sentence Correction

It took the museum decades of creative and persistent effort and it acquired the outstanding Rembrandt collection.

(A) and it acquired the outstanding Rembrandt collection
(B) before their outstanding Rembrandt collection had been acquired
(C) and finally it had an outstanding Rembrandt collection there
(D) but finally an outstanding Rembrandt collection was acquired at last
(E) to acquire its outstanding Rembrandt collection

OA is E
What is the best modifier to use here? An Expert pls.THanks