Which of the following is correct about chrysophytes?
I. Found in fresh and marine water
II. Microscopic plankton 
III. Cell walls are embedded with  ${\mathrm{CaCO}}_3$
IV. Most of them are photosynthetic

• A

  I and III only

• B

  I, III and IV only

• C

  I, II and IV only

• D

   I and IV only