TNF-Receptor Signaling Commonly Includes Several Steps That Are Regulated by Ubiquitination

TNF-receptor signaling commonly includes several steps that are regulated by ubiquitination. One important step following TNF-receptor stimulation is the:

A) K48-linked ubiquitination and degradation of a TRAF protein, itself a ubiquitin-ligase
B) K48-linked ubiquitination of the TNF-receptor cytoplasmic tail, leading to its degradation
C) K63-linked ubiquitination of the TNF-receptor, providing a docking site for TRAF protein binding
D) K48-linked ubiquitination of NIK, the NF $\kappa$ B-inducing kinase
E) K63-linked ubiquitination of cIAP, leading to its binding to NIK, the NF $\kappa$ B-inducing kinase