Synthesis of 2-Phenyl-2-Butanol from Grignard Reagent The question is this:

2-Phenyl-2-Butanol can be synthesized by three different combinations of a grignard reagent and a ketone. Show each combination.

I can only think of one. 


Butanone with Br-Mg-Ph


I can't think of anything else. 

I'm not too sure if this will work:

phenylbutanone withe Br-Mg-Me

now i'm stuck. i can't think of the last one.
Hint: The carbon atom bearing the OH group in the product has three substituents--phenyl, methyl, and ethyl. Any one of these groups could be introduced as a Grignard reagent, with the appropriate ketone. You have already correctly deduced one of the three possibilities.