Double-Negative Thymocytes Initiate Rearrangement at the _____ Locus (Loci)before All

Double-negative thymocytes initiate rearrangement at the _____ locus (loci) before all other T-cell receptor genes.

A) γ and δ
B) β
C) α and β
D) α,γ,and δ
E) β,γ,and δ.