Usage of "Which" or "That" when referring to a noun followed by "OF"

Hi,

I seem to have some problem in understanding the usage of "that" and "Which" in the following constructions:

Development of new technology, which can reduce the inefficiency, .....

In the above sentence, what does "which" refer to - "Development" or "new technology"

I would greatly appreciate if someone can shed some light on the same.

Thank you