Which of the following is a possible factor that has prevented humans from making changes that would allow them to rely entirely on nonrenewable resources?

question 2 options:

a)

politicians have removed all barriers, they just need the money.

b)

the idea that since nonrenewable resources are still available, there is no need to switch yet.

c)

efficient technology doesn't always exist.

d)

both b and c

e)

all of the above