Answer:
The sentence fragment that does not contain a capitalization error is on the guitar.
Step-by-step explanation:
The sentence fragment that does not contain a capitalization error is on the guitar because it does not require any capital letter. Names of people, titles, nationalities, languages, names of the days of the week, months of the year, holidays and festivals should be capitalized.
Seasons do not require capitalization if they are used as generic common nouns. However, they do require capitalization if the name of the season is used in a title.
All things considered, the correct version of the sentence would be: Mrs. Hernandes played a haunting Spanish melody on the guitar at the summer festival -or Summer Festival, if it is the name of the festival.