In the Class I MHC Pathway of Antigen Presentation,cytoplasmic Proteins $\kappa$

In the class I MHC pathway of antigen presentation,cytoplasmic proteins are tagged for proteolytic degradation by covalent linkage with which of the following molecules?

A) Calreticulin
B) Nuclear factor (NF) - $\kappa$ B
C) Tapasin
D) Ubiquitin
E) Calnexin