What is the product of 4[cos ( 2π /3 )+isin ( 2π /3 )] and 2[cos ( π /3 )+isin ( π /3 )] ?
a. 6[cos ( π /3 )+isin ( π /3 )]
b. 6[cos (π )+isin (π )]
c. 8[cos ( π /3 )+isin ( π /3 )]
d. 8[cos (π )+isin (π )]