# How many stereo isomers does this molecule have $CH_3CH =CHCH_2CHBrCH_3$

$(a)\;8 \\(b)\;2\\(c)\;4\\(d)\;6$

The given compound may be written as
Both geometrical isomers (c is transform) and optical isomers is possible in the given compound.
No of optical isomers $=2^n=2^1=2$
Where n=no of optical isomers $=2+2=4$
Hence c is the correct answer.