You have been asked to synthesize 5,6-dimethylhept-3-yne: the structure of 5,6-dimethylhept-3-yne. When you look for reactants in the storage room, you find the following: 
a) Ethyne and 4-methylhexene 
b) Ethyne and 2-methylhexene 
c) Propyne and 4-methylhexene 
d) Propyne and 2-methylhexene