Which prefix indicates not, as in forming 'impossible'?

Which prefix indicates not, as in forming 'impossible'?

• A. un-
• B. in-
• C. im-
• D. non-

Answer: (C)

Negation prefixes show that a word means “not.” In English, which prefix you use often depends on the sound that comes after. Before p, b, or m, the negation prefix changes to im- so the word sounds smoother. So, for a base word like possible, the not form is im- to make impossible, meaning not possible. The other negation prefixes exist, but they don’t give the standard spelling for this word—unpossible or inpossible aren’t the correct forms here, and non- would hint at a different idea. That’s why im- is the right choice.

Negation prefixes show that a word means “not.” In English, which prefix you use often depends on the sound that comes after. Before p, b, or m, the negation prefix changes to im- so the word sounds smoother. So, for a base word like possible, the not form is im- to make impossible, meaning not possible. The other negation prefixes exist, but they don’t give the standard spelling for this word—unpossible or inpossible aren’t the correct forms here, and non- would hint at a different idea. That’s why im- is the right choice.