In the following question on idioms and phrases, choose the option that best explains the meaning of the expression “a dime a dozen”.

Introduction:
Idioms are fixed expressions whose meanings cannot be understood simply by translating each word literally. The phrase a dime a dozen originates from American English, where a dime is a small coin and a dozen means twelve units. This idiom is widely used in daily conversations, media, and literature to comment on how common or ordinary something is. Recognising idiomatic meanings helps you understand real world English more accurately.

Given Data / Assumptions:

- Idiom: a dime a dozen. - Options include different possible meanings about value and quantity. - We must select the explanation that matches standard idiomatic usage.

Concept / Approach:
Literally, a dime a dozen suggests that you can get twelve items for just a dime, which is a very small amount of money. Figuratively, it means that the things being described are extremely common and not considered special or valuable. The correct option should capture both the sense of plentifulness and the lack of special worth. It does not praise strength in numbers or advise buying more; rather, it downplays importance or rarity.

Step-by-Step Solution:
Step 1: Recall common usage, such as Good ideas are rare, but bad suggestions are a dime a dozen. Step 2: Focus on the implied meaning: these items or people are very common and not highly valued. Step 3: Evaluate option C, Very common and of no particular value, and see that it directly matches this meaning. Step 4: Check option A, Strength is in numbers, which talks about power in groups, not commonness and low value. Step 5: Notice that option B focuses on people who say bad things, which is too narrow and unrelated to the idiom's general meaning. Step 6: See that option D, You save more if you buy in large numbers, describes a shopping strategy and not the figurative value judgment the idiom makes.

Verification / Alternative check:
Use the idiom in additional sentences: In big cities, coffee shops are a dime a dozen or Influencers promising instant success are a dime a dozen. In both cases, the phrase clearly means that such things are everywhere and not particularly special. If we tried to apply the meaning Strength is in numbers or You save more if you buy in large numbers, the sentences would stop making sense, confirming that option C is correct.

Why Other Options Are Wrong:
Option A introduces a completely different proverb about collective strength, not about commonness or triviality. Option B mentions people who say bad things, which might also be common but does not reflect the generic nature of the idiom applied to many objects and situations. Option D is descriptive of bulk purchasing, whereas a dime a dozen is not advice but a comment on how ordinary something is. These choices therefore misrepresent the idiom's actual usage.

Common Pitfalls:
Learners sometimes try to connect idioms directly with everyday financial logic, thinking a cheaper price always implies a good deal. Here, however, the cheapness highlights lack of importance or special quality. The best way to master idioms is to learn them in context with example sentences and to note whether the speaker's attitude is positive, negative, or neutral. For a dime a dozen, the attitude is usually negative or dismissive.

Final Answer:
Very common and of no particular value is the correct explanation of the idiom a dime a dozen.