The IUPAC name of the compound

Question

$ (a)\;1,1-dimenthyl-2-propene \\ (b)\;3- methyl -1-butene \\ (c)\;2-vinyl propane \\ (d)\;1- isopropyl \;ethylene $

Answer 1

http://clay6.com/mpaimg/jee%20c%2070.JPG

It is correct IUPAC name is $ 3- methyl -1-butene$

Hence b is the correct answer.