In the following sentence, some part may have an error. Identify the part with the error, or select "No error" if the sentence is correct: "If you are in the wrong gears (A) / the car won't be (B) / able to climb the hill. (C) / No error (D)".

Introduction / Context:
Error-spotting questions test your ability to notice small but important grammatical or usage mistakes in English sentences. This particular sentence talks about driving a car uphill and uses the phrase "in the wrong gears". To answer correctly, you must understand normal English usage for mechanical terms like "gear" and how they are used in such expressions.

Given Data / Assumptions:

• The sentence is divided into four parts: (A) If you are in the wrong gears (B) the car won't be (C) able to climb the hill. (D) No error.
• We must find which part contains the grammatical or usage error.
• The context is operating a car and selecting the right gear.
• Expressions like "in the wrong gear" are common in English.

Concept / Approach:
In normal English, when we talk about the setting chosen for a car's transmission, we almost always use the singular "gear" in phrases such as "in the wrong gear" or "in first gear". Even though a car has multiple gears, the driver is only in one gear at a particular moment. Therefore the natural phrase is "in the wrong gear", not "in the wrong gears". The rest of the sentence is grammatically correct, so the error lies in the use of the plural noun in part (A).

Step-by-Step Solution:
Step 1: Read part (A) "If you are in the wrong gears" and check whether it matches standard idiomatic English. Step 2: Recall common expressions: "in the right gear", "in the wrong gear", "change gear". These all use the singular "gear". Step 3: Realise that at any one moment the car is engaged in a single gear, so "gears" is logically and grammatically odd here. Step 4: Examine part (B): "the car won't be". This is fine because it continues into "able to climb the hill". Step 5: Examine part (C): "able to climb the hill." This is grammatically correct and meaningful. Step 6: Having checked all parts, conclude that part (A) contains the error: we should say "If you are in the wrong gear".

Verification / Alternative check:
You can verify with any English driving manual or standard phrasebook that the usual expression is "drive in the wrong gear" or "be in the wrong gear for the speed or slope". The plural "gears" might be used in a different structure, such as "modern cars have five gears", but not in the positional phrase "in the wrong gear". Therefore, identifying A as the erroneous part matches real-world usage.

Why Other Options Are Wrong:

• B: "the car won't be" correctly leads into "able to climb the hill", so there is no error here.
• C: "able to climb the hill" is standard English expressing capability and has no grammatical problem.
• D: "No error" is wrong because we have clearly identified an error in part A; thus, the sentence is not error-free.

Common Pitfalls:
Some students overlook small number (singular/plural) mistakes because they focus mainly on tenses or prepositions. Others may be influenced by the fact that cars indeed have several gears and therefore feel that "gears" is logical. However, English often uses singular nouns in fixed expressions where only one option is active at a time. Recognising these patterns is essential for doing well in error-detection questions.

Final Answer:
The error is in part (A); the correct phrase should be "in the wrong gear".