Final answer:
The given run-on sentence is: Aimée Marcoud, a trapeze artist, performed under the name Miss Fillis, she retired at the age of fifty-five.
Step-by-step explanation:
The run-on sentence in the given options is:
Aimée Marcoud, a trapeze artist, performed under the name Miss Fillis, she retired at the age of fifty-five.
A run-on sentence occurs when two or more independent clauses are joined without proper punctuation or coordination. In this sentence, two independent clauses 'Aimée Marcoud, a trapeze artist, performed under the name Miss Fillis' and 'she retired at the age of fifty-five' are joined without a coordinating conjunction or proper punctuation.
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