**Core Concept**
Thermal modalities are used in physical therapy and pain management to apply heat or cold to specific areas of the body to achieve therapeutic effects. These modalities can be classified based on the temperature and duration of application.

**Why the Correct Answer is Right**
To identify which option is not a thermal modality, we need to examine each choice. Thermal modalities typically involve the application of heat or cold to the body. This can be achieved through various methods, including ultrasonography (heat), shortwave diathermy (heat), and cryotherapy (cold).

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a thermal modality. Instead, it is a type of electromagnetic radiation used in physical therapy to promote healing and reduce pain.
**Option B:** This option is not a thermal modality. It involves the application of electrical currents to the body to stimulate muscle contractions and promote healing.
**Option C:** This option is not a thermal modality. It involves the application of low-intensity laser or light-emitting diodes to promote tissue repair and reduce pain.

**Clinical Pearl / High-Yield Fact**
It is essential to differentiate between thermal and non-thermal modalities to provide appropriate treatment for patients. Thermal modalities are often used for pain management and tissue repair, while non-thermal modalities may be used for muscle stimulation and other therapeutic effects.

**Correct Answer:** B. Electrical stimulation. Electrical stimulation is a type of non-thermal modality used in physical therapy.