This is my grammar quiz of finding out the ungrammatical.
Elephants are large land-dwelling mammals characterized by their long snouts and ivory tusks. Only three of the hundreds of elephant species that once existed remain at this time, namely, savanna, forest, and Asian elephants. The only two continents which these surviving species can be found are Africa and Asia. Climate change, habitat loss, and human intrusion have contributed to the elephant's status as an endangered animal.
My non-native teacher said the answer should be (C) for not placing 'In' before 'Which'. Is she correct? And the free grammar checker in the web also pointed out (C) but for different reason. It suggested to switch 'Can be found' to some other verb in active voice, which I don't get it at all.