The correct option is
A Chlorella
Chlorella is an autotroph which prepares its own food with the help of photosynthesis. It is a single-cell green algae which has chlorophyll pigment chlorophyll-a and -b in its chloroplast. It is more or less equivalent to soybean and spinach having high proteins, lipids, and varieties of vitamins. It is used as health supplements. It is the rich source of iron, magnesium, and zinc.
So, the correct answer is option A.