What sequence of steps represents the best synthesis of 4-heptanol (CH3CH2CH2)2CHOH?
a. CH3CH2CH2MgBr (2 moles) + formaldehyde (CH2=O) in diethyl ether followed by H3O+
b. (CH3CH2CH2)2CHMgBr + formaldehyde (CH2=O) in diethyl ether followed by H3O+
c. CH3CH2CH2MgBr + butanal (CH3CH2CH2CH=O) in diethyl ether followed by H3O+
d. CH3CH2CH2CH2MgBr + acetone [(CH3)2C=O] in diethyl ether followed by H3O+