Paperchase undergraduate organic chemistry!

May 2014
I really need help with this problem! please help!

Reaction of compound A with pyridinium chlorochromate yielded compound B, which upon reaction with one molar equivalent of ethyl lithium gave compound C. Reaction of C with phosphoric acid under reflux produced compound D. Compound D has a molecular formula of C8H14. Reaction of compound D with 40% hydrogen bromide yielded compound E. Compound E has a molecular formula C8H15Br. 13C-NMR of compound A shows a total of four 13C signals. Compound B produced a yellow precipitate when treated with 3,5-dinitrophenylhydrazine but no silver mirror with Tollen¹s reagents and C generates a cloudy precipitate under Lucas Test conditions within 10 seconds. D decolourises a red solution of Br2 in CCl4.

What is compound A?

If you could please let me know how you got to the answer too, that would be great! thanks :)