'What does that say' challenges you on homographs.
As you will have been discovering, English has a rich range of words that look the same but can sound differently, and/or carry very different meanings, according to their context. How good are you at distinguishing between members of these pairs, or even larger groups?
Perhaps somewhat confusingly, 'plant' can also refer to a complete factory ('a car plant' ~ which sounds like something very science-fictional until you've understood it!), or any unspecified number of freestanding machines, e.g. boilers or bulldozers (Answer 4).