Here's a problem to solve: Which statement best compares single-celled and multi-celled organisms?

Among the 4 following options, which is the correct answer?

- A: Tissues in a single-celled organism are like the cells in a multi-celled organism.
 
- B: The nucleus in a single-celled organism is like the skin of a multi-celled organism.
 
- C: Organelles in a single-celled organism are like the organs in a multi-celled organism.
 
- D: The cytoplasm in a single-celled organism is like the nervous system in a multi-celled organism.
 