Which of the following nonrenewable energy resources is generally the least efficient at producing electrical energy?
a. oil
b. coal
c. natural gas
d. uranium-238

explanation:

i think option no d is the correct answer

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

they it depends on if one believes about radioactivity, they make a geiger counter beep but maybe it was going to beep anyway electronics do wierd things all the time or it was programmed to beep near certain metals.