Parts of the following sentence have been highlighted and given as options. Select the option that contains an error.
Immediately after the prince got down from his horse to drink some water from the pond nearby, an eagle flew over the horse and an unicorn ran in front of him.

Correct option is D

Option (d) contains the error. The error in "an unicorn" lies in the incorrect usage of the article "an" before a word that begins with a consonant sound. The correct usage should be "a unicorn" because "unicorn" starts with a 'y' sound, which is a consonant sound.
· Grammatical rule used: The article "a" is used before words that begin with a consonant sound, while "an" is used before words that begin with a vowel sound.
· Example: An apple a day keeps the doctor away; A university is an institution of higher education.