Final answer:
The Roborovski hamster is another species besides the Syrian hamster. It is one of several species increasing in popularity as pets, with concerns about their escape and potential invasiveness.
Step-by-step explanation:
Another species of hamster besides the Syrian hamster is B) Roborovski hamster.
Explanation: Aside from the Syrian hamster, which is the most commonly known species, there are various other species of hamsters that are popular as pets around the world. Among those, the Roborovski hamster is appreciated for its diminutive size and swift movements. In the context of pet trade, hamsters like the Roborovski hamster, Chinese hamster, Djungarian hamster (also known as Winter White Russian Dwarf hamster), and the Campbell's dwarf hamster are often found.
These species are part of the genus Phodopus and have been bred and traded in significant numbers, particularly in the United States over recent years. The increasing popularity of unique small mammals as pets has raised concerns about their escape from enclosures and potential to become invasive if released into non-native environments.