The correct answer is C. Trichophyton tonsurans

Correct Answer Explanation

T. tonsurans, T. violaceum, T. soudanense, T. gourvilli, T. yaoundei, and occasionally T. rubrum cause an endothrix pattern. T. schoenleinii causes favus in which hyphae and air spaces are seen in the hair shaft. A bluish-white fluorescence pattern is seen with Wood’s lamp. Clinically, patients have thick yellow cup-shaped crusts (scutula); scarring and secondary infection may result. M. canis, M. audouinii, M. ferruginosum, M. distortium display a yellow fluorescence on Wood’s lamp examination.

Incorrect Answer Explanation

Organisms that cause an ectothrix pattern of tinea capitis include M. canis, M. audouinii, M. ferruginosum, M. distortium, M. gypseum and occasionally T. rubrum.

References

Hay RJ. Tinea Capitis: Current Status. Mycopathologia. 2017 Feb;182(1-2):87-93. PMID: 27599708