Which of the following may be separated by ordinary physical methods? Select one: cis 2 bromo-2-butene and trans-2-bromo 2 butene (2039)-1,2-dibromobutane and (25,3R)-1.2- dibromobutane (R)-3-bromo-1 butene and (9-3-bromo-1 butene (R)-2-bromobutane and (5)-2-bromobutane