Number of isomeric alcohols of molecular formula C6H14O which give positive iodoform test is

The iodoform test is positive for alcohols with formula  R-CHOH-CH3 . Among C6H14O isomers, the ones with  positive iodoform test are:   I.  CH3-CH2-CH2-CH2-CHOH-CH3                      2- Hexanol   II. CH3-CH2-CHCH3-CHOH-CH3           3- Methyl-2-Pentanol   III. CH32CH-CH2-CHOH-CH3             4- Methyl-2-Pentanol   IV. CH33C-CHOH-CH3        3 , 3- Dimethyl-2-butanol