The correct answer is C. Bead.
Explanation
The words bin, bit, and bid belong to the same group because the vowel sound is the same. This sound is represented with the symbol /ɪ/. On the other hand, the word bead has a different vowel sound because this sound is longer and the way it produces is different, also it is represented with a different symbol /iː/. According to this, the word that does not belong is a bead, because it has a different vowel sound.
