Which Combination of Reagents Is to Be Preferred for the Synthesis

Which combination of reagents is to be preferred for the synthesis of 2,4-dimethylhexane by the Corey-Posner,Whitesides-House procedure?

A) Lithium diisobutylcuprate + sec-butyl bromide
B) Lithium dimethylcuprate + 2-bromo-4-methylhexane
C) Lithium dimethylcuprate + 4-bromo-2-methylhexane
D) Lithium diisopropylcuprate + 1-bromo-2-methylbutane
E) Lithium di(2-methylbutyl) cuprate + isopropyl bromide