Which three meridians are known to connect to the root of the tongue?

The three meridians known to connect to the root of the tongue are the Heart (HT), Spleen (SP), and Kidney (KD) meridians. Understanding the relationship between these meridians and the tongue is crucial in Traditional Chinese Medicine (TCM).

The Heart meridian plays a pivotal role as it is responsible for governing the blood and housing the mind (Shen). The tongue is considered an important organ of speech and expression, and its health is closely related to the Heart's function, particularly in how it reflects the state of blood and vitality.

The Spleen meridian is integral in producing and transforming Qi and blood from food intake. A healthy Spleen function supports the nourishment of the tongue. Therefore, an imbalance in the Spleen can often manifest in changes in the tongue's appearance and function.

The Kidney meridian is vital in TCM for its role in water metabolism and storing essence. The Kidneys also support the Heart and Spleen's functions. The connection to the tongue reflects the Kidneys' role in nourishment and vitality throughout the body, affecting the tongue's health indirectly.

Thus, the correct option encompasses these three meridians that have significant connections to the root of the tongue