MCQmediumRules for 'a' before consonants and 'an' before vowels

In the sentence 'The sun is the source of energy in the earth,' why is 'the' used before 'sun'?

Options

aBecause 'sun' starts with a consonant.
bBecause it's the second mention.
cBecause the sun has no alternative.check_circle
dBecause it is an unspecified object.

Key Points

Rule 8 states: "We also use the to refer to something that has no alternative. e.g. The sun is the source of energy in the earth."

Source

Class 6English Grammar and Composition Chapter 3: Articles: a, an, the Topic: Rules for 'a' before consonants and 'an' before vowels

Aligned to the NCTB national curriculum.