To run efficiently and productively, a fusion reaction must operate at temperatures greater than __ degrees C.

A) 100

B) 2,000

C) 1,000,000

D) 100,000,000

E) 350,000,000

d

To determine the correct answer, we need to understand the conditions required for a fusion reaction to occur efficiently and productively. Fusion reactions involve the combining of atomic nuclei to form a heavier nucleus. In order for this to happen, the atoms need to overcome the electrostatic repulsion between their positively charged nuclei.

This repulsion can be overcome at extremely high temperatures, because at high temperatures, the atoms gain enough kinetic energy to overcome the repulsion and come close enough together to allow the strong nuclear force to bind them together.

To put it simply, the particles must collide with enough energy to overcome the repulsion and initiate the fusion process. The minimum temperature required for efficient fusion reactions is around 100 million degrees Celsius.

So, among the given options, the correct answer is:

D) 100,000,000 degrees C