Step 1: Understanding the Concept
The juxtaglomerular apparatus (JGA) helps regulate blood pressure and filtration in the kidney.
Step 2: Parts of the JGA
It is made of juxtaglomerular cells in the arteriole wall, which release renin, and the macula densa, a patch of cells in the distal tubule wall.
Step 3: Compare the options
Macula lutea is in the retina, and the maculae of saccule and utricle are in the inner ear.
Final Answer:
JG cells together with the macula densa form the JGA.
\[ \boxed{\text{(C) }\text{Macula densa}} \]