单选题 To their great surprise, they found the floodwater had damaged the building's foundation.
A. underlain B. underlined C. undertaken D. undermined

【正确答案】 D

【答案解析】damage破坏，损坏；underlain(underlie的过去分词形式)位于……之下，成为……基础；underline在……下划线，强调；undertake从事；undermine破坏。