Took a 100 question practice exam last night using the Total Tester software and received this question:
Of the protocols listed below, which operates at the Application Layer of the OSI model:
A) HTTP

FTP
C) HTTPS
D) SMTP
They all do! I picked A for no reason in particular and the question was marked correct, but I could see a candidate's head exploding if this ever got through the rounds and made it onto an exam.