The words jump and stunt are examples of which sound device? . a) alliteration b) consonance c) assonance d) onomatopoeia

Alliteration is the repetition of the same consonant in the beginning of neighboring words, so this is not the correct answer.
Consonance is the repetition of the same consonant anywhere in the word, so this too is not correct.
Onomatopoeia is the imitation of the sounds in nature, such as: knock, etc., again, not correct.
The correct answer is C. assonance, which is the repetition of the same vowel - here it is "u" in jump and stunt. 

Aa i believe is the answer to your question