What is the point the speaker is trying to
题型：单项选择题
问题：
What is the point the speaker is trying to make about technology development
A．A mature technology requires less innovation.
B．Technical evolution is close to maturation in certain fields.
C．New types of energy are expected to mature in the near future.
D．Nanomaterials or photonics and carbon nanotubes are environmentally friendly.