How many structural isomers exist with the formula `C_(4)H_(10)O`?

Explanation

The total number of structural isomers for the compound of the formula `C_(4)H_(10)O` is seven.
`CH_(3)CH_(2)CH_(2)CH_(2)OH` n-Butyl alcohol
`CH_(3)CH (OH) CH_(2)CH_(3)` sec. Butyl alcohol
`(CH_(3))_(2)CHCH_(2)OH` Isobutyl alcohol
`(CH_(3))_(3)COH` tert. Butyl alcohol
`CH_(3)CH_(2)CH_(2)OCH_(3)` Methyl propyl either
`CH_(3)CH_(2)OCH_(2)CH_(3)` Diethyl ether
`(CH_(3))_(2) CHOCH_(3)` Methyl isopropyl ether