Question

Which power source has been least developed?

Answer 1

Answer:

the answer the the question is wind

Answer 2

On the question, there should be a graph.  On the graph, you'll have various lines colored blue, red, yellow, turquoise, and dark green.  You basically just wanna look for the line that is the lowest, which should be the dark green line.  Which is the wind line.

So simply put, the answer is Wind.

This is also the answer for "Which power source has been least consumed?".  It's basically the same thing, and same answer.