Classifying alcohols by OH group attachment

Steps:

• Define alcohol types: primary (OH on carbon with 1 alkyl group), secondary (2 alkyl groups), tertiary (3 alkyl groups).
• Parse each option's formulas to identify the carbon attached to OH and count its alkyl substituents.
• Check for one of each type in a single row.
• Select the row matching all three classifications.

Why D is correct:

• D contains CH3CH2OH (primary: OH on CH2 with 1 CH3), CH3CH(OH)CH3 (secondary: OH on CH with 2 CH3), and (CH3)3COH (tertiary: OH on C with 3 CH3), per substitution rules.

Why the others are wrong:

• A: All structures are primary alcohols like CH3OH or CH3CH2OH.
• B: Includes amines (NH) and only primary/secondary alcohols, no tertiary.
• C: Mixes primary/secondary with incomplete tertiary notation, missing clear third type.

Final answer: D