What is a characteristic of all forms of tinea?

The characteristic of tinea that makes it highly contagious is due to its nature as a fungal infection. Tinea, commonly known as ringworm, can easily spread from person to person or through contact with contaminated surfaces, such as towels, clothing, or shared items. This contagious aspect is especially pronounced in certain environments, like schools and gyms, where many individuals might come into close contact with one another.

While it’s true that some forms of tinea can lead to hair loss, it does not happen in all cases or can vary in significance. Similarly, not all tinea infections are found only on the scalp; they can occur on various parts of the body, including the feet (athlete's foot), groin (jock itch), and body (tinea corporis). Resistance to treatment can vary based on the specific type of fungal pathogen involved and the individual's health, but it is not a universal characteristic of all tinea infections. Thus, the defining feature of tinea's contagion aligns with option B.