请教何为明确的时间点？prep1-137

137。  The Swedish warship Vasa, sunk in 1628 and raised in 1961, was preserved in the cold water of Stockholm harbor, where low salinity inhibits the growth of marine borers that in most seas devour every exposed scrap of a sunken ship's wooden hull.
(A) was preserved in the cold water of Stockholm harbor, where low salinity inhibits
(B) being preserved in the cold water of Stockholm harbor, because the low salinity there is able to inhibit
(C) and preserved in the cold water of Stockholm harbor, the low salinity there inhibits
(D) having been preserved in the cold water of Stockholm harbor, whose low salinity inhibits
(E) had been preserved in the cold water of Stockholm harbor, because of low salinity there inhibiting

这道题目答案是A。

A是看起来比较顺眼，但是sunk in 1628 and raised in 1961，是不是明确指出了它是had been preserved？

过去完成时，开始与过去，终止与过去，持续了一段时间，效果也止于过去。

同问，raised in 1961 不是说明 在1961 preserve这个动作已经完成了吗？

为什么不用过去完成时呢