In the following idiom based question, choose the option that best expresses the meaning of the phrase "a wet blanket".

Introduction / Context:
This question tests your knowledge of common English idioms. The phrase "a wet blanket" is used figuratively and does not literally refer to a blanket soaked in water. Idioms like this often appear in conversation, novels and examinations, and they cannot be understood correctly by translating each word separately. Instead, you must know or infer the figurative meaning. Here you are asked to select the option that best captures the sense of the idiom in everyday usage.

Given Data / Assumptions:

• The idiom given is "a wet blanket".
• The options describe different possible meanings, including people, places and situations.
• We assume the question refers to common conversational English, not a rare or technical sense.
• The idiom is usually used to describe a person at social gatherings or group activities.

Concept / Approach:
"A wet blanket" originally comes from the idea of using a damp blanket to smother or put out a fire. Figuratively, the idiom describes someone who "puts out" the excitement or enthusiasm of others. Such a person may complain, refuse to participate, criticise suggestions or generally make fun activities feel dull. Therefore, we must look for an option that describes a person who discourages enjoyment or enthusiasm. Any option that describes an object, a place or a physical safety device without the figurative sense will not be correct.

Step-by-Step Solution:
Step 1: Recall the figurative meaning of "a wet blanket" as a person who dampens the mood or enthusiasm of others. Step 2: Read each option and check whether it refers to a person or something else, and whether it matches this figurative idea. Step 3: Identify that "A person who discourages enjoyment or enthusiasm" exactly describes the typical use of the idiom. Step 4: Confirm that the other options talk about safety nets, places, tricks or situations that do not match the established figurative meaning.

Verification / Alternative check:
Imagine a situation where friends are excited about going to a party, but one person keeps complaining that it will be boring or a waste of time. Someone might say, "Do not be such a wet blanket." Clearly, they are criticising the person for spoiling the fun. This usage fits perfectly with the option that mentions "a person who discourages enjoyment or enthusiasm". If we try to insert the other meanings into similar sentences, they either do not fit grammatically or do not convey the same emotional effect. This contextual test confirms that the chosen meaning is correct.

Why Other Options Are Wrong:
"A safety net of precaution from fires" reflects the literal idea of a wet blanket smothering flames but does not capture the figurative, social sense of the idiom. "An extremely uncomfortable place to sleep" misinterprets "blanket" without considering the metaphor of dampening excitement. "A trick to shoo away unwelcome guests" is creative but unrelated to standard usage. "A situation that suddenly becomes dull" shifts focus from a person to a situation; although there is some overlap in effect, the idiom normally labels a person rather than an event. Thus, only one option is accurate and precise.

Common Pitfalls:
A typical mistake is to interpret idioms too literally. Because the words "wet" and "blanket" are easy to picture, students may think of physical objects or sleeping arrangements. Another pitfall is to accept an option that seems vaguely related to dullness even if it misses the key idea that the idiom usually refers to a person. To avoid such errors, try to recall a real sentence or scenario where you have seen or could naturally use the idiom. If you can slot the option meaning into that context without distortion, it is likely to be correct.

Final Answer:
"A wet blanket" means a person who discourages enjoyment or enthusiasm.