A 22 years old male patient presents with a complaints of severe itching and white scaly lesions in the groin for past month. Which of the following is most likely to be the causative agent –
This patient has : -          

Lesions in groin
Severe itching. Both occurs in Tinea cruris. But white colour of lesion creates confusion here as the typical lesion of T. cruris is red (erythmatous) scaly lesion. However, color of the lesion is not much of the significance if all other features suggest the diagnosis of T. cruris.

Further, other options can easily be exclude :-

Malassezia furfur (T. versicolor) affects trunk & shoulder, and there is no itching.
Candida infection usually occurs in immunocompromized individuals. Lesions are characterized by reddened plaques with satellite pustule (peripheral pustule). Itching may occur but it is not severe as in Dermatophytic infection.
Trichophyton rubrum
Candida albicans
Candida glabrata
Malassezia furfur