Under a microscope, gram-negative bacteria (when dyed with the gram stain) appear

Gram negative bacteria appear red or pink following a gram stain procedure

This is what i found on google “phytoplankton, tiny organisms that live in the ocean, are autotrophs. some types of bacteria are autotrophs. most autotrophs use a process called photosynthesis to make their food.” i hope this you for what your looking for

The answer is option b.