Solution:
Here, the sentence talks about the 'octopus' as general class of things. Since we are referring to general things, we need to use the definite article 'a/an'. The word 'octopus' starts with a vowel and therefore 'an' will be used.

Solution:
The given sentence in a way shows comparison. The structure of a sentence that shows a proportionate increase is in the order: the + comparative adjective + clause + the + comparative adjective + clause. Hence Option A is correct.

Solution:
Here, specific place 'library' has been mentioned from where books shall be borrowed. Hence, definite article 'the' will be used.

Solution:
No article is required.

Solution:
As the band's name is specified, we can understand that 'Anu' plays the band's guitar. Hence the guitar is a specific guitar. Thus we can use 'the' here. 'Drums' is also a specific noun here as it is a part of the band's instruments. Thus we will use 'the' here as well.

Solution:
The definite article 'the' is used before specific things. Here, we are referring to the specific information that 'you' need. Hence, we must use 'the' before it. No article is used before proper nouns. Here 'page 15' is a proper noun. Therefore, no article is used before it.

Solution:
Use 'an' before words such as "hour" which sound like they start with a vowel even if the first letter is a consonant. Also use 'an' before letters and numbers which sound like they begin with a vowel, such as "F" or "8". Here MLA begins with 'em' and therefore 'an' article will be used.