The correct answer is option 4, which states that unicellular organisms are found in all three kinds of organisms mentioned: algae, fungi, and protozoa.

Let`s break down each option to understand why option 4 is correct:

Option 1 states that only algae (option 1) have unicellular organisms. This is incorrect because fungi and protozoa also have unicellular organisms.

Option 2 states that only fungi (option 2) and protozoa (option 3) have unicellular organisms. This is also incorrect because algae also have unicellular organisms.

Option 3 states that only algae (option 1) and protozoa (option 3) have unicellular organisms. This is incorrect because fungi also have unicellular organisms.

Option 4 states that all three kinds of organisms (algae, fungi, and protozoa) have unicellular organisms. This is correct because algae, fungi, and protozoa all include both unicellular and multicellular organisms.

In conclusion, option 4 is the correct answer as it includes all the organisms (algae, fungi, and protozoa) that have unicellular organisms.