Exploring Word Formation by Adding a Prefix

The question asks us to determine which of the given words form a meaningful English word when the letter 'C' is placed directly before them.

Let's examine each word:

• ONE: When 'C' is added before 'ONE', it becomes 'CONE'. 'CONE' is a recognized English word (e.g., an ice cream cone, a traffic cone).
• TWO: Adding 'C' before 'TWO' results in 'CTWO'. This is not a standard English word.
• BEN: Adding 'C' before 'BEN' results in 'CBEN'. This is not a standard English word.
• MUG: Adding 'C' before 'MUG' results in 'CMUG'. This is not a standard English word.

Based on this analysis, only the word 'ONE' forms a meaningful English word ('CONE') when the prefix 'C' is added.

Identifying the Correct Option

We need to find the option that correctly states that only 'ONE' forms a meaningful word.

• Option 1 suggests 'MUG' and 'ONE'. This is incorrect because 'MUG' does not form a meaningful word.
• Option 2 suggests 'ONE' and 'TWO'. This is incorrect because 'TWO' does not form a meaningful word.
• Option 3 suggests 'BEN'. This is incorrect because 'BEN' does not form a meaningful word.
• Option 4 suggests 'ONE'. This aligns with our finding that only 'ONE' forms a meaningful word ('CONE').

Therefore, the correct choice is the one that identifies 'ONE' as the only word forming a meaningful English word after adding the prefix 'C'.