没错，答案就是would have got lost，不能是had got lost或would get lost。请注意句中的without which，它隐含有一个条件，相当于if we hadn’t had a map。这里的主句和从句谓语之所以分别用would have got lost和hadn’t had，是因为前面的句子Fortunately we had a map用的是一般过去时，说明这里是针对过去情况作假设。原句意思是：

Fortunately we had a map, without which we would have got lost. 幸亏我们有张地图，否则我们就会迷路了。（否则我们就会迷路了=要是我们当时没有那张地图，我们就会迷路了）