Answer:
Cyanobacteria. (Ans. A)
Explanation:
Cyanobacteria are prokaryotes, are a phylum of bacteria. They are also called as blue-green algae and obtain their energy through the process of photosynthesis. They are commonly found in fresh water and terrestrial environment such as land, in rocks even in animal cells (fur). 
Cyanobacteria are photosynthetic (oxygenic) bacteria. They harvest the energy of sun, absorb carbon dioxide and release O2. Cyanobacteria also contain chlorophyll such as plants and algae and convert carbon dioxide to sugar through the process of carbon fixation.
Cyanobacteria lack nucleus and other organelles like found in algae and plants. Instead of these they have double outer cell membrane and folded inner thylakoid member which are used in the process of photosynthesis. 
 
        
             
        
        
        
Its either A or C. thats all i can say though but B and D you can rule out. I hope i helped a little 
        
             
        
        
        
Answer: 
Deoxyribonucleic acid (DNA) hold the hereditary material that acts as a blueprint for the development and functioning of life process on the earth. It is a blueprint for every cell in every organism.
Its major function is to encode the DNA sequence of amino acid by using the triplet genetic code that code for a specific protein that perform a specific function in the body that are necessary for the normal function of the life processes.