Question

Choose the prefix for the word 'Possible' to make it opposite:

• A. Un
• B. Im
• C. Ill
• D. In

Hint:

To easily remember when to use the prefix im-, check if the root word begins with M, B, or P (think of the mnemonic acronym MBP). Examples: *Patient $\rightarrow$ Impatient*, *Balance $\rightarrow$ Imbalance*, *Moral $\rightarrow$ Immoral*.

Answer 1

The Correct Option is B

Concept: A prefix is an affix placed before the stem of a word to alter its meaning. In English grammar, negative prefixes such as un-, in-, il-, ir-, and im- are used to create antonyms (opposites). The choice of a negative prefix often depends on the initial letter of the base word. A specific phonological rule determines the placement of the prefix

im-: The prefix 'in-' shifts phonetically to 'im-' when it is attached to a root word starting with the bilabial consonants 'p', 'b', or 'm'. This phonetic adjustment happens because both 'm' and 'p' are bilabial sounds made using both lips, making the transition much smoother to pronounce.

Step 1: Analyze the starting letter of the base root word.
The base word provided in the question is 'Possible'. Let us identify its initial letter and phonetic classification:

• Initial Letter: 'P'

• Phonetic Type: Bilabial plosive consonant

Step 2: Test the given prefixes against the root word.
Let us systematically evaluate each option to see which combination yields a linguistically valid English word:

• (A) Un + Possible = Unpossible: This is structurally incorrect and does not exist in standard English lexicon.

• (B) Im + Possible = Impossible: This follows the bilabial assimilation rule perfectly. The resulting word correctly means "not able to occur, exist, or be done."

• (C) Ill + Possible = Illpossible: This is an invalid lexical combination.

• (D) In + Possible = Inpossible: This violates the phonetic rule of bilabial modification. The 'n' sound naturally assimilates into an 'm' sound before a 'p'.
Therefore, the correct prefix is 'Im', which creates the word Impossible. This corresponds directly to option (B).