The following sentence has been split into four segments. Identify the segment that contains a grammatical error.

There is some monkeys / on the roof of the / carriage but Madhav / does not see them.

The erroneous part is option 2) i.e. 'There is some monkeys.' 

Key Points

• ​The word "some" is typically used with uncountable nouns or plural nouns when referring to an indefinite quantity.
• However, when referring to a specific number of monkeys on the roof, it would be more appropriate to use "there are" instead of "there is."
• "Is" is used with singular nouns, while "are" is used with plural nouns.
• In this case, since we are talking about multiple monkeys (a plural noun), the correct verb form should be "are."
• By using "are" instead of "is," we maintain grammatical agreement between the plural noun "monkeys" and the verb "are."
• Also, the pronoun "them" (in the latter part of the sentence) is used to refer to the monkeys. "Them" is a plural pronoun, indicating that there are multiple monkeys.

Therefore, the correct answer is: There are some monkeys on the roof of the carriage, but Madhav does not see them.