The correct answer is B. Organelles.
Step-by-step explanation
An organelles are units that are part of the unicellular organism or a cell. Each of these units has various specific functions provide structure to the organism of which they are part. According to the above, organelles are the component of unicellular organisms that have the same purpose of organs in multicellular organisms, because their functions contribute to the life of organisms. So, the correct answer is B. Organelles.