Final answer:
Homo habilis and Homo erectus coexisted for a significant period, which fits option (c) of the given choices. Homo habilis was not the direct ancestor of Homo erectus, as was once thought, and the fossil record indicates an overlap between the two species.
Step-by-step explanation:
The time period during which Homo habilis and Homo erectus overlapped can be best described by the option (c) Homo habilis and Homo erectus coexisted for a significant period. Homo habilis, which was once thought to be the first to create stone tools and appeared in the fossil record around two to three million years ago, was not the direct ancestor of Homo erectus. Instead, these species coexisted, and there has been significant debate regarding their taxonomic positions and relationships with other early archaic Homo species. Homo erectus, which evolved about 1.9 million years ago in East Africa and eventually migrated to Eurasia, overlapped with Homo habilis before Homo habilis ceased to exist.