In the question below, a paragraph is split into several parts. Examine each part for grammatical accuracy and select the option that correctly identifies which parts are grammatically correct or incorrect.

(A) This year’s increased rainfall have caused frequent waterlogging across the city. (B) If the drainage network is maintained before the heaviest spells, (C) neighborhoods will be spared repeated flooding. Farmers report that reservoirs have filled early, helping irrigation (D) but also raising the risk of pests. While forecasts predict continued showers, but officials advise residents to avoid low-lying underpasses. (E) Because timely alerts have been issued this year, many commuters have started leaving home earlier to avoid gridlock.

Correct Answer: A and D are incorrect

Let us analyze each sentence/part of the given paragraph for grammatical accuracy:

Part (A): "This year’s increased rainfall have caused frequent waterlogging across the city."
Error: The subject of this clause is "increased rainfall", which is an uncountable singular noun. Therefore, it requires the singular verb "has" instead of the plural verb "have".
Correction: "This year’s increased rainfall has caused frequent waterlogging across the city."
Hence, Part A is grammatically incorrect.

Part (B): "If the drainage network is maintained before the heaviest spells,"
This is a standard conditional clause using proper subject-verb agreement and prepositional usage.
Hence, Part B is grammatically correct.

Part (C): "neighborhoods will be spared repeated flooding. Farmers report that reservoirs have filled early, helping irrigation"
This sentence uses correct passive construction ("will be spared"), proper tense agreement, and clear structure.
Hence, Part C is grammatically correct.

Part (D): "but also raising the risk of pests. While forecasts predict continued showers, but officials advise residents to avoid low-lying underpasses."
Error: Redundancy error. The subordinating conjunction "While" and the coordinating conjunction "but" should not be used together to connect the main and subordinate clauses in the same sentence.
Correction: "While forecasts predict continued showers, officials advise residents to avoid low-lying underpasses." (Remove "but").
Hence, Part D is grammatically incorrect.

Part (E): "Because timely alerts have been issued this year, many commuters have started leaving home earlier to avoid gridlock."
This sentence correctly uses the causal conjunction "Because" without any redundant conjunctions, and maintains proper subject-verb agreement ("alerts have been", "commuters have started").
Hence, Part E is grammatically correct.

Conclusion: Parts A and D contain grammatical errors. Therefore, the option identifying the incorrect parts is "A and D are incorrect".