Answer: No options listed.
Explanation: Economic growth happens when there is an increase in the inflation-adjusted market value of various goods and services in a period of time. There is an increase in the number of items produced or services offered which increases the money in an economy. Some factors that lead to economic growth are land, capital or technological growth and advancement.
I believe the answer is: Sheet metal
Self tapping screws are made by creating a gap in the connector within the thread of a crew, which creates a flute and cutting edge just like what we see on tap. This makes self tapping screws able to tap their own hole in a sheet metal while normal screws can't.