In the question below, a sentence is provided with one part highlighted in bold. The bold segment may or may not contain a grammatical error. Choose the option that best replaces the highlighted part to make the sentence grammatically correct. If the sentence is already correct as it stands, choose 'No replacement required' as your answer.

Whenever it is raining, waterlogging in streets and roads is the most common problem the city faces.

The correct option is it rains.

Logical Explanation:

The sentence describes a recurring condition or general truth about an event that happens repeatedly under specific circumstances. In English grammar, adverbs of frequency and conjunctions of time like "whenever" indicate habitual actions, routines, or universal facts.

For general truths, routines, and recurring events, we use the Simple Present Tense (e.g., it rains). In contrast, the Present Continuous Tense (e.g., it is raining) is used for an ongoing action happening specifically at the moment of speaking, which makes it contextually incorrect here.

Let's analyze all the options:
• it rain: Incorrect because the third-person singular pronoun "it" takes the singular verb form "rains" according to Subject-Verb Agreement rules.
• No replacement required: Incorrect because "it is raining" wrongly uses continuous tense for a general recurring event.
• it rains: Correct. It correctly uses the Simple Present Tense to express a routine or general occurrence.
• it is rained / it is rains: Incorrect due to ungrammatical verb formulations.

Corrected Sentence:
"Whenever it rains, waterlogging in streets and roads is the most common problem the city faces."