Structural isomers of C3H8O alcohols by type

Steps:

• Identify the molecular formula C3H7OH as C3H8O for monohydric alcohols.
• Determine alkyl group isomers for C3H7: straight-chain (CH3CH2CH2-) and branched ((CH3)2CH-).
• Form alcohols: CH3CH2CH2OH (primary, 1° carbon attached to OH) and (CH3)2CHOH (secondary, 2° carbon attached to OH).
• Confirm no tertiary alcohol possible, as it requires a 3° carbon with OH, needing at least 4 carbons total.

Why C is correct:

• C states 1 primary, 1 secondary, 0 tertiary, matching the two structural isomers classified by carbon attachment to OH per IUPAC definitions.

Why the others are wrong:

• A overcounts primaries by including stereoisomers or duplicates.
• B ignores the branched isomer, listing only straight-chain.
• D includes impossible tertiary or miscounts totals.

Final answer: C