In each of the following questions, find out which part of the sentence has an error. The sentence is divided into three parts labelled A, B and C, and part D suggests that the sentence has no error. Identify the part that contains a grammatical or usage error in the sentence: I may spend this summer vacations with one of my friends in the backwaters of Kerala.

Introduction / Context:
This error spotting question checks your understanding of number agreement between determiners and nouns, as well as natural phrasing in English. The sentence talks about plans for spending summer holidays with a friend in Kerala. You need to decide which part of the sentence sounds incorrect in standard English usage or whether the sentence is fully correct.

Given Data / Assumptions:
- Full sentence: I may spend this summer vacations with one of my friends in the backwaters of Kerala. - Part A: I may spend. - Part B: this summer vacations. - Part C: with one of my friends in the backwaters of Kerala. - Part D: The sentence is grammatically correct; no error.

Concept / Approach:
The phrase this summer vacations is not correct because the singular demonstrative this should be followed by a singular noun, for example this vacation, or the noun vacations should be preceded by a plural demonstrative like these. In standard English, we usually say this summer vacation or these summer vacations, depending on whether we refer to one period or multiple periods. The rest of the sentence, including in the backwaters of Kerala, is acceptable and natural. Therefore, the error lies in the mismatch between this and vacations in part B.

Step-by-Step Solution:
Step 1: Examine part A, I may spend. This is a correct introductory phrase expressing possibility. Step 2: Examine part B, this summer vacations. The determiner this is singular, while vacations is plural. For correct agreement, we should use this summer vacation or these summer vacations. Step 3: Examine part C, with one of my friends in the backwaters of Kerala. This phrase is grammatically sound. The expression backwaters of Kerala correctly describes the famous waterways in that state. Step 4: Because only part B has a clear error of number agreement, part B must be selected as the incorrect segment.

Verification / Alternative check:
Rewrite the sentence with correct agreement: I may spend this summer vacation with one of my friends in the backwaters of Kerala. Now, the singular this matches the singular vacation, and the sentence sounds natural. Alternatively, you could say I may spend these summer vacations, but that requires changing this to these. Since only the original phrase this summer vacations needed correction, our choice of part B as the error is confirmed.

Why Other Options Are Wrong:
Part A is correct because the modal verb may is properly used to express possibility. Part C is correct because the phrase with one of my friends in the backwaters of Kerala is grammatically and idiomatically acceptable. Part D is wrong because the sentence does contain an error in part B, so it is not fully correct.

Common Pitfalls:
Learners sometimes overlook small agreement errors because they focus on larger structures only. Another common mistake is to carry over patterns from other languages where determiners may function differently. To avoid such errors, pay attention to the pairing of this with singular nouns and these with plural nouns, and practise with common time expressions like this year, these years, this summer, and these summers. Such practice will make it easier to notice mismatches quickly in exam settings.

Final Answer:
The part containing the error is this summer vacations, which should be changed to this summer vacation or these summer vacations.