Answer:
The correct answer is letter "B": megacities.
Step-by-step explanation:
A megacity is an urban space with more than ten (10) million inhabitants according to the definition provided by the United Nations Department of Economic and Social Affairs (2014). The largest megacity by the start of 2020 is Guangzhou in China with 45.6 million inhabitants followed by Tokyo in Japan with 40.2 million inhabitants.