Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
|  | organ system |  | organs |
| --- | --- | --- | --- |
| The | circulatory system | is composed of | the heart, blood, blood vessels, and lymphatics |
| The | nervous system | is composed of | the brain, spinal cord, and nerves |
| The | digestive system | is composed of | include the mouth, stomach, and intestines |
| The | endocrine system | is composed of | pituitary and thyroid glands, ovaries and testes |
| The | integumentary system | is composed of | the skin, hair, nails, and sweat glands |
| The | muscular system | is composed of | muscle tissue |
| The | reproductive system | is composed of | the uterus, the fallopian tubes, the cervix, the vagina, the penis, the testes |
| The | respiratory system | is composed of | the nose, larynx, trachea, diaphragm, bronchi, and lungs |
| The | skeletal system | is composed of | bones, cartilage, and joints |
| The | urinary system | is composed of | the kidneys, ureters, urinary bladder, and urethra |
| The | excretory system | is composed of | sweat glands, the liver, the lungs and the kidney system |
Question:
"The heart, blood, blood vessels, and lymphatics belong to what organ system?" Select the correct choice to answer the question or fill in the blank.
Choices:
(A) respiratory system
(B) muscular system
(C) circulatory system
(D) digestive system
Answer:
(C) circulatory system