Steel changed people’s lives by making possible the

a. invention of radio.
b. development of electricity.
c. construction of skyscrapers.
d. establishment of time zones.

I believe the answer is: c. construction of skyscrapers

Steels is used as the main material to create building foundation, which provide significantly stronger and balanced structure compared to woods or iron. This allow architects to design building with more height with lesser risk of falling down.

answer; allows decision to stand;