The error is in the third part of the sentence.

We need to replace ‘An’ with ‘A’. Article ‘A’ is used before words which begin with a vowel but are pronounced as with a consonant. As— A European, a unique chance, a one-rupee note, a usual sight, a universal truth.

So, the correct answer is C.

The error is in the second part of the sentence.

We need to replace ‘a’ with ‘an’. Some Abbreviations are there which are pronounced with a Vowel sound and therefore article ‘an’ is used before them. E.g. an M. A.; an M. P.; an M. L. A.; an F. I. R; an S. D. O.; an H. M. T.; an R. T. O. etc.

So, the correct answer is B.

The error is in the fourth part of the sentence.

We need to replace ‘an ugly and a foolish man’ with ‘an ugly and foolish man’. When more than one Noun or Adjective points to one Person or Thing only, Article A or An is used before the first word only, and its form is also determined by the same first word.

So, the correct answer is D.

The error is in the third part of the sentence.

We need to replace ‘a’ with ‘an’. If an Adjective /Adverb comes before a Noun, Article A or An is used before the Adjective / Adverb, and its form is determined by the nearest word.

So, the correct answer is C.

The error is in the fourth part of the sentence.

We need to replace ‘couple of people’ with ‘a couple of people’. Article A or An is used before some Numerical Expression. The more common of such expressions are— a couple, a dozen, a score, a hundred, a thousand, a million, a lot of, a great many of, etc.

So, the correct answer is D.

The error is in the first part of the sentence.

We need to replace ‘a red and blue pencil’ with ‘a red and a blue pencil’. When more than one Noun or Adjective points to one Person or Thing only, Article A or An is used before the first word only, and its form is also determined by the same first word. But if they point to different Persons or Things, Article A or An is used before each word, and its form is determined by each word separately.

So, the correct answer is A.

The sentence is correct as it is. So, the correct answer is E.

The error is in the first part of the sentence.

We need to replace ‘A poet and novelist’ with ‘A poet and a novelist’. We need to replace ‘a red and blue pencil’ with ‘a red and a blue pencil’. When more than one Noun or Adjective points to one Person or Thing only, Article A or An is used before the first word only, and its form is also determined by the same first word. But if they point to different Persons or Things, Article A or An is used before each word, and its form is determined by each word separately.

So, the correct answer is A.

The error is in the first part of the sentence.

We need to replace ‘great many of’ with ‘a great many of’. Article A or An is used before some Numerical Expression. The more common of such expressions are— a couple, a dozen, a score, a hundred, a thousand, a million, a lot of, a great many of, etc.

So, the correct answer is A.

The sentence is correct as it is. So, the correct answer is E.