Which among the following will give 3,3–dimethylbut–1–yne on reaction with  NaNH2/∆

1,2–dibromo–3,3–dimethylbutane undergo dehydrohalogenation reaction in the presence of NaNH2 in liquid NH3  and forms 3,3–dimethyl but–1–yne.2,2–dibromo–3,3–dimethylbutane undergo dehydrohalogenation reaction in the presence of NaNH2 in liquid NH3 and forms 3,3–dimethylbut–1–yne.