Which of the following molecules contains a carbonyl group? Methyl methanoate, 1-ethoxybutane, 1-propanol, and 2-pentanone.

• A. 1-ethoxybutane and 1-propanol
• B. 2-pentanone and methyl methanoate
• C. 1-ethoxybutane and 2-pentanone
• D. 1-propanol and methyl methanoate

Answer: (B)