Plants are responsible for a very important energy transformation, as shown. At left, a small grey circle is followed by an arrow pointing right to a large grey circle with a small white circle centered in it. The 4 arrows point to a vertical row of 4 images, 1 arrow per image. From top there are a medium sized grey circle with a small white circle centered in it, then a small grey circle, then another small grey circle, then another medium sized grey circle with a small white circle centered in it. Then comes + Energy. At the top of the vertical row of 4 images is the label Nucleus. At the bottom of the vertical row of 4 images is the label Nucleus.

Which energy transformation does the picture best illustrate?

radiant to chemical
nuclear to mechanical
chemical to thermal
mechanical to chemical