Explanation:

- Kidney

- The kidneys are vital organs responsible for filtering waste and excess fluids from the blood to form urine.

- They help regulate the body's electrolyte balance and blood pressure but do not secrete hydrochloric acid.

- Heart

- The heart is a muscular organ that pumps blood throughout the body.

- It does not have any role in secreting digestive acids like hydrochloric acid.

- Stomach

- The stomach is part of the digestive system and plays a critical role in digestion.

- The stomach lining secretes hydrochloric acid, which helps in breaking down food and killing pathogenic bacteria.

- Correct Answer: Option 3 - Stomach

- Brain

- The brain is the control center of the body, responsible for processing sensory information and coordinating actions.

- It does not secrete digestive acids.