As Thymocytes Develop, They Are Classified on the Basis of the State

As thymocytes develop, they are classified on the basis of the state of their T-cell receptors and which of the following?

A) Which class of MHC they express on their surface
B) The state of the immunoglobulin heavy and light chains on their surface
C) The presence of coreceptor proteins CD4 and CD8 on their surface
D) The expression of the transcription factor, FoxP3
E) None of the answers are correct.