Question

When you go to pick strawberries, you are easily able to separate the ripe red berries from the green foliage, the white blossoms and the green, still-forming berries. This has led to the suggestion that _____.​

Answer 1

this has led to the suggestion that the colour evolve to express the purpose of detecting the fruit

Answer 2

The fact that you can pick the right strawberries to eat may suggest that the color vision may have evolved to the express purpose of detecting fruit.
If it wasn't for color vision, you couldn't differentiate the barriers that are edible. This characteristic evolved in the sense of better survival.