Which sentence is a compound sentence? a. freddy won the race, and jenna came in second. b. tori will eat lunch with her grandmother on sunday. c. before nina left for school, she put on her raincoat. d. benicio and dani went to the birthday party together.

The compound sentence is A) Freddy won the race, and Jenna came in second. A compound sentence has two independent clauses joined by a comma (or semicolon). Each independent clause has to be able to "stand on it's own," meaning it has to be a complete sentence on its own with a subject and verb. You could put a period at the end of each of these independent clauses in this sentence.

Hope this helps! :)

(d) it was complex and capable of highly organized efforts.