His singing enthralled the entire audience.

Answer: Option B

Disappointed : sad or displeased because someone or something has failed to fulfil one's hopes or expectations.
Captivated : attract and hold the interest and attention of; charm.
Entertained : provide (someone) with amusement or enjoyment.
Surprised : feeling or showing surprise.
Enthralled : capture the fascinated attention of.

Synonym of Enthralled is Captivated