In the following sentence on error spotting, identify the part that contains a grammatical error. A rate of growing is different for different sectors, but the service sector always grows faster than agriculture.

Introduction / Context:
This question belongs to the common error spotting type in English grammar sections of competitive exams. The sentence deals with economic growth in different sectors. The challenge is to identify which part contains an incorrect phrase or construction. Here, the focus is on the correct noun phrase to describe how fast something increases over time.

Given Data / Assumptions:
• The sentence is divided into parts labelled A, B, C and a final option D for No error.• Part A reads: A rate of growing is different.• The context is comparing growth across different sectors of the economy.• The natural economic term is rate of growth, not rate of growing.

Concept / Approach:
In English, we usually talk about the rate of growth of an economy, company, or sector. Growth is the correct abstract noun in this collocation. The word growing is a present participle that functions as a continuous verb or a gerund in other contexts, but not in this standard phrase. The phrase A rate of growing is different is unidiomatic and incorrect. Therefore, the error lies in part A. The other parts of the sentence, which describe different sectors and compare the service sector with agriculture, are grammatically acceptable.

Step-by-Step Solution:
Step 1: Read the complete sentence: A rate of growing is different for different sectors, but the service sector always grows faster than agriculture.Step 2: Replace A rate of growing with the standard economic expression The rate of growth to see if it improves the sentence.Step 3: The corrected sentence becomes: The rate of growth is different for different sectors, but the service sector always grows faster than agriculture.Step 4: Check parts B and C for additional errors in tense, articles, or comparison. They are grammatically fine.Step 5: Conclude that the sole error is in part A, which uses the wrong noun form.

Verification / Alternative check:
Consider how newspapers and economics textbooks phrase similar ideas. You will frequently see expressions like growth rate of the service sector, rate of growth of manufacturing, and growth rate is different across regions. None of these ever use rate of growing. This real world evidence supports the conclusion that rate of growth is the accepted collocation and confirms that part A contains the error.

Why Other Options Are Wrong:
Option b: for different sectors, but the service sector is structurally sound. It introduces a contrast using but and correctly places the noun phrase the service sector.Option c: always grows faster than agriculture correctly compares the growth of the service sector with that of agriculture using the comparative faster.Option d: No error is incorrect because part A clearly contains a non standard expression.

Common Pitfalls:
Students sometimes focus only on obvious grammar markers like verb tense and prepositions and miss errors in collocation, that is, the natural pairing of words in a language. Phrases like rate of growing might appear logical to someone who thinks literally, but idiomatic usage demands rate of growth. In error spotting, paying attention to standard phrases used in news articles, academic writing, and textbooks can help you recognise these subtle mistakes.

Final Answer:
The incorrect phrase is in part A; it should be The rate of growth instead of A rate of growing. Correct answer: A.