In the following sentence on articles and noun phrases, the underlined part needs improvement. Choose the option that best corrects the sentence, or select No improvement if it is already correct. The majority of the rain fed Indian rivers either dry up or become trickle after the monsoon.

Introduction / Context:
This question checks understanding of article usage and countable nouns in English grammar. The sentence describes what happens to rain fed Indian rivers after the monsoon, and the candidate must choose the grammatically correct version of the underlined part. The focus is on whether the noun trickle needs an article and whether subject verb agreement is correct.

Given Data / Assumptions:

• The subject is the majority of the rain fed Indian rivers, which is treated as a plural idea in common usage.
• The verbs attached to this subject are either dry up or become trickle.
• The noun trickle is a countable singular noun when used in this sense.
• The sentence describes a general pattern that happens after the monsoon season.

Concept / Approach:
In English, when we use a singular countable noun like trickle to refer to one small flow, we usually need an article such as a. The phrase become trickle without an article is unnatural. Also, the verb form should agree with the plural idea the majority of the rivers, which takes a plural verb dry instead of dries in normal modern usage. Therefore, we need to keep the plural verb dry up and add the article a before trickle.

Step-by-Step Solution:
Step 1: Identify the main subject: the majority of the rain fed Indian rivers, which refers to many rivers. Step 2: Recognise that for this kind of subject, standard modern English usually uses a plural verb such as dry up. Step 3: Examine the noun trickle and recall that it is a singular countable noun when used to mean a small thin flow of water. Step 4: Apply the rule that singular countable nouns require an article or another determiner, so we need a trickle. Step 5: Combine the correct verb and noun phrase to get either dry up or become a trickle after the monsoon.

Verification / Alternative check:
We can read the final sentence aloud: The majority of the rain fed Indian rivers either dry up or become a trickle after the monsoon. This sounds natural and grammatically complete. If we remove the article and say become trickle, the phrase sounds incomplete. If we use a singular verb like dries with the plural idea of rivers, that also sounds wrong in modern standard usage. Grammar reference books confirm that with a plural idea like majority of the rivers, a plural verb is acceptable and common, and a singular countable noun needs an article.

Why Other Options Are Wrong:
Option a uses the trickle, which is possible but less natural here, because we are not talking about one specific known trickle. Option c uses dries for the majority of the rivers, which reads as a mismatch between subject and verb. Option d contains an trickle, which is incorrect because an is used before vowel sounds, and trickle begins with a consonant sound. Option e, no improvement, is wrong because become trickle without an article is grammatically defective.

Common Pitfalls:
Learners sometimes overlook the need for articles with singular countable nouns, especially when the focus is on verbs like dry up. Another common mistake is confusion around majority, which looks singular but often takes a plural verb when it clearly refers to many items. Exam questions like this target those small details. Careful reading and checking each noun phrase and verb separately can prevent these errors.

Final Answer:
The corrected and most natural form is either dry up or become a trickle after the monsoon, which appears in option b.