Improvement of sentence: a part of the following sentence is considered incorrect. Choose the word that best improves the sentence. If no improvement is needed, choose the option marked No improvement. The sales boy told the consumer not to touch the products on display.

Introduction / Context:
This question tests your understanding of everyday English vocabulary and correct word choice in a commercial context. The sentence describes a conversation between a sales boy and someone who is looking at goods in a shop. You have to select the most natural and idiomatic noun for that person in standard English.

Given Data / Assumptions:

• The sentence is: The sales boy told the consumer not to touch the products on display.
• The focus is on replacing the word consumer with a better choice.
• Options are buyer, shopper, customer, consumer, and No improvement.
• The situation is a normal retail shop where people are looking at products.

Concept / Approach:
In English, different nouns are used for people who purchase or may purchase goods. Consumer is a broad economic term used in economics, marketing, and law to refer to anyone who uses goods or services. Customer and shopper are more personal and are used in day to day shop situations. The natural collocation in a sentence where a sales boy is speaking to someone in the shop is usually customer.

Step-by-Step Solution:
Step 1: Read the sentence and identify the person who is being addressed. Step 2: Notice that the scene is a shop with products on display and a sales boy speaking. Step 3: Compare the meanings of consumer, customer, buyer, and shopper in this context. Step 4: Choose customer because it is the standard word for a person being served in a shop.

Verification / Alternative check:
Imagine a typical shop notice or conversation: The sales boy told the customer not to touch the products on display. This sounds completely natural. A notice might also say Customers are requested not to touch the display items. This confirms that customer is the most appropriate word here.

Why Other Options Are Wrong:

• buyer: Suggests a person who has already decided to buy, but here the person may only be looking.
• shopper: Possible, but less precise than customer when the sales boy is addressing a specific person.
• consumer: Formal economic term, not the usual choice in direct shop conversation.
• No improvement: Wrong because consumer is not the best collocation in this sentence.

Common Pitfalls:
Students often pick consumer because they have seen it in textbooks related to commerce and consumer rights. However, competitive exams test natural usage, not only textbook terms. Another error is to choose shopper because it sounds correct, but in a direct interaction customer is preferred.

Final Answer:
Correct option: customer.