A correctly formed Yoruba compound sentence joins two related clauses smoothly, often with a connector such as sì (and/also), as seen in sentences like they arrived and they left, he went and bought it, and he worked and slept. Each of those reads as a natural, grammatically sound coordination of two actions.
Ó lọ s'òun òun does not follow this pattern; the phrase repeats òun awkwardly and lacks the coherent structure a proper compound sentence needs, making it the example of faulty coordination among the choices given.
When asked to spot an incorrectly joined sentence, check whether the coordinating word links two complete, sensible clauses; a sentence that repeats or garbles a pronoun without adding a second clause is a sign of faulty construction.
