Cartilage is not found in :

• A: Nose: The human nose has a framework of bone and cartilage. The upper part of the nose is bony, while the lower portion is cartilaginous. The septum, the structure that divides the two nostrils, is also partially made up of cartilage. Cartilage provides the nose with its shape and flexibility.
• B: Ear: The outer ear, or pinna, is primarily composed of cartilage. This cartilaginous structure gives the ear its shape and allows it to be somewhat flexible. Cartilage in the ear is crucial for capturing sound waves and directing them into the ear canal.
• C: Kidney: The kidney is an organ of the urinary system. Its primary function is to filter waste products from the blood and excrete them in the form of urine. Structurally, the kidney is made up of nephrons, blood vessels, and a complex tubular system. It doesn't have any cartilaginous tissue. Therefore, among the options provided, the kidney is the only organ that doesn't contain cartilage.
• D: Larynx: Often called the voice box, the larynx is situated in the neck and is involved in breathing, producing sound, and protecting the trachea from food aspiration. It is made up of several cartilage structures, including the thyroid cartilage, cricoid cartilage, and arytenoid cartilages. These cartilages give the larynx its rigidity and structure, ensuring it remains open and functions properly.

That is why, The correct option is C: Kidney.