According to Alfred Wegener, the earth originally had one continent called?

Alfred Wegener proposed the theory of continental drift, which posited that the continents were once joined together as a single landmass known as Pangaea. This supercontinent existed during the late Paleozoic and early Mesozoic eras, around 335 to 175 million years ago, before it began to break apart due to tectonic forces. Wegener's idea was revolutionary at the time and laid the foundation for modern plate tectonics, highlighting the movement of continents over geological time.

The other options represent different geographical terms or regions but do not correspond to Wegener’s concept of a single ancient landmass. Eurasia refers to the combined landmass of Europe and Asia, Transcontinentia is not a recognized scientific term in relation to continental formations, and Africa is simply one of the continents that separated from Pangaea. Thus, Pangaea is the correct term that aligns with Wegener’s hypothesis about the Earth's geological history.