Read the following sentence and identify the part that contains an error, if any: 1. Four famous Sikh shrines in Delhi will go green 2. by employing solar energy 3. to meet its daily power needs from April. 4. No error

Introduction / Context:
This is an error detection question, which is a common format in competitive English exams. The sentence is divided into four parts, and you must find which part contains a grammatical mistake. The sentence describes four famous Sikh shrines in Delhi moving towards using solar energy to meet their power needs. The key concepts tested here are subject verb agreement and correct use of pronouns with plural nouns.

Given Data / Assumptions:
- Part 1: Four famous Sikh shrines in Delhi will go green.
- Part 2: by employing solar energy.
- Part 3: to meet its daily power needs from April.
- Part 4: No error.
- The subject of the sentence is four famous Sikh shrines, which is clearly plural.

Concept / Approach:
To solve error detection questions, you should first identify the main subject and then check whether verbs and pronouns agree with it. In this sentence, the subject shrines is plural. Therefore, any pronoun referring back to it should be plural as well. However, in part 3, the pronoun used is its, which is singular. The correct plural pronoun should be their. This mismatch between plural subject and singular possessive pronoun is the grammatical error we need to locate.

Step-by-Step Solution:
Step 1: Identify the subject of the sentence: four famous Sikh shrines in Delhi, which is plural.
Step 2: Check each part for pronouns or verbs that must agree with this subject.
Step 3: Notice in part 3 the phrase to meet its daily power needs from April, where its is singular but refers to the plural shrines.
Step 4: Conclude that part 3 contains the error and that the correct form should be to meet their daily power needs from April.

Verification / Alternative check:
Read the corrected sentence with the plural pronoun: Four famous Sikh shrines in Delhi will go green by employing solar energy to meet their daily power needs from April. Now every part sounds grammatically correct. No other part of the sentence breaks basic rules. The future tense will go green is fine, and the phrase by employing solar energy correctly describes how they plan to go green. Therefore, part 3 is the only part needing correction.

Why Other Options Are Wrong:
- Part 1: Four famous Sikh shrines in Delhi will go green is grammatically correct and clearly states the subject and main action.
- Part 2: by employing solar energy correctly uses the gerund employing to describe the means by which they will go green.
- Part 4 (No error): this option is incorrect because we have already identified a clear pronoun agreement error in part 3, so the sentence is not error free.
- No error in any part: this general option is also wrong for the same reason; there is definitely an error in part 3.

Common Pitfalls:
Many candidates read quickly and focus only on big words like solar energy or daily power needs, overlooking small but crucial pronouns. Subject pronoun agreement errors are subtle yet very common in exams. A good strategy is to always track back every pronoun and check whether its number and sometimes gender match the noun it refers to. Here, carefully linking its to the plural shrines reveals the problem immediately.

Final Answer:
The error is in Part 3 because its should be their, so Part 3 is the correct choice.