Explanation:

- Blood clots form due to the action of specific blood components.

- Option 1: Chondrocytes

- These are cells found in cartilage, not involved in blood clotting.

- Option 2: Erythrocytes

- Also known as red blood cells, they transport oxygen but don't aid in clotting.

- Option 3: Platelets

- These cell fragments are crucial for blood clot formation. They gather at the site of a blood vessel injury, stick together, and release chemicals to activate the coagulation cascade.

- Option 4: Lymphocytes

- These are a type of white blood cell involved in immune response, not clotting.