Which of the following is a “prefix"?

Choose the best answer from the options below:
A a group of letters added to the end of a word
B a word part that contains the basic meaning of a word
C a group of letters that appear at the beginning of a word
D a word part that means the opposite of the word’s meaning

C a group of letters that appear at the beginning of a word

The correct answer is C: a group of letters that appear at the beginning of a word.