The correct option is B latest
Latter means occurring or situated nearer to the end of something than to the beginning, the meaning of latter is similar to later only. Latest is used in order to indicate that something must happen at or before a particular time and not after that time. In this sentence, a particular time has been indicated for Tim, and in other words it means that Tim won't be arriving after everyone since he is travelling by car (slowest). The answer becomes Option B