Focus on the single best clue, a creamy curd like white film on the tongue. This soft, milk curd appearance is the hallmark of oral thrush.
Oral thrush is an infection by Candida albicans. Its plaques are loosely adherent, can be wiped away, and often reveal a red sore base, which separates it from fixed white lesions. So candidiasis is the answer.
Eliminate the others on morphology. Lichen planus shows lacy white Wickham striae that stay put when you scrape, very different from curd. Histoplasmosis tends to ulcerate the mouth and appears in disseminated or immunosuppressed settings, not as a wipeable patch. Aspergillosis is mainly a lung and sinus disease and does not present as a tongue curd.
So a scrapable creamy white tongue patch is candidiasis.
\[\boxed{\text{Candidiasis}}\]