The trick is to use the correct reactants in order and give the corresponding letters that would eventually yield the target molecule. You can only use what is given.
I tried doing this using the lithium cyclohexane and making it into a dialkyl cuprate but I get stuck after the addition of the ethyl group (D,G,F....?) so I figured this way was wrong (I think).
I then tried the grignard way (in our class, the professor said to assume the R-Li reacts the same way as R-MgBr for purposes of simplicity) and got up to D,B,J,C,I to give acetophenone... can you just neutralize again to get the target? Is this even remotely correct?
The above is of utmost concern, but if you have time, can anyone corroborate this one:
and I get FEHGBD.