Plants absorb light most efficiently in the blue and red parts of the light spectrum.

Option 1: Violet and orange is not correct. Violet light is partially absorbed by plants, but orange light is less efficiently absorbed as it falls outside the key wavelengths that photosynthesis uses.

Option 3: Indigo and Yellow: Like orange, both these colors fall outside of the optimal range for plant absorption. Yellow light is relatively weakly absorbed by plants, and while indigo light is part of the blue spectrum, it is not absorbed as efficiently as pure blue light.

Option 4: Yellow and Violet: These colors are both at the extremes of the spectrum that plants use for photosynthesis and are not absorbed as effectively as blue and red light.

So, the correct answer is 2: Blue and Red light are the types of light that plants absorb the most for photosynthesis. This absorption is used to energize electrons, which are instrumental in creating glucose during photosynthesis.