- At the park, happily, played, the kids.
- The kids played happily at the park.
- At the park played happily the kids.
- Happily played the kids at the park.
The correct sentence structure in English is Place-Subject-Adverb-Verb. The place (at the park) should come first, followed by the subject (the kids), the adverb (happily), and finally, the verb (played). The correct option (b) follows this structure.