The entire sentence is underlined (or should be). That means both subject and verb are underlined, so check that they agree. In choice A, the subject is satire (singular) and the compound verb is seizes and exaggerates (both singular), so the subject agrees with its verbs. The sentence also ends in a pronoun, them, so check that it clearly refers to a noun in the sentence and agrees with that noun. Them can only refer to foibles or flaws, so there is no pronoun error. Choice A looks good.

Choice B has only a minor grammatical error, in that the placement of typically after the verb is somewhat unidiomatic in this context. More serious is that this choice changes the meaning of the sentence and makes it less logical. The original sentence says that satire ... seizes on ... foibles OR flaws AND exaggerates them. Choice B swaps the conjunctions: satire ... seizes on ... foibles AND flaws OR exaggerates them. The first construction is more logical. The nouns foibles and flaws are synonymous, so OR (in the sense of "in other words") is more appropriate. The conjunction joining the verbs is even more important. In choice A, satire takes (seizes) foibles or flaws AND exaggerates them. In choice B, satire EITHER takes (seizes) those foibles OR exaggerates them; however, one cannot exaggerate them without first seizing on them. The use of AND between verbs in choice A implies an escalation, and this sense is lacking in choice B where OR is used. Eliminate B.

In choice C, the pronoun at the end is it, which doesn't agree with foibles or flaws. Eliminate C.

Choice D is redundant, because the verb tends to and the adverb typically express the same idea of a general truth. You could use one or the other but not both. Eliminate D.

In choice E, the two verbs are not parallel: seizes (present indicative tense) and is exaggerating (present continuous or progressive tense). Verbs in the -ing form are rarely correct on the GMAT; mostly they are used to make a sentence wordier. Eliminate E.

To recap: Eliminate B for changing the meaning and making the sentence less logical. Eliminate C for lack of pronoun agreement. Eliminate D for being redundant. Eliminate E for violating parallel construction. The answer is A.

harshitpuri wrote:the whole sentence is underlined and A is right answer,
but how pronoun them is right here?

Them refers, properly and unambiguously, to foibles or flaws. There are no other plural nouns in the sentence. It use is also observes parallel construction. The sentence has two verb phrases: seizes on a public official's foibles or flaws, where foibles or flaws serves as an object; and exaggerates them, where them also serves as an object.