Group J consists of 4 students: Putri Ayu, Novita Jumianingsih, Nurotun Solihah, and Nursanti Setiorini. The document then defines and provides examples of simple sentences, compound sentences, and complex sentences. Simple sentences contain one independent clause, compound sentences contain two independent clauses joined by a coordinating conjunction, and complex sentences contain one independent clause and one dependent clause joined by a subordinating conjunction.