Which of the following sentences best exemplifies a compound-complex sentence?

A compound-complex sentence is a combination of two or more independent clauses and at least one dependent clause. The selected sentence—"She enjoys reading, and he loves painting because it relaxes him"—includes two independent clauses, "She enjoys reading" and "he loves painting," which can stand alone as complete thoughts. Additionally, it contains a dependent clause, "because it relaxes him," which cannot stand alone and adds more information about why he loves painting.

In contrast, the other sentences do not meet the criteria for a compound-complex structure. One option is a simple sentence that contains only one independent clause. Another includes a dependent clause but lacks a second independent clause. The third option has a dependent relative clause but does not present the necessary structure of a compound-complex sentence with multiple independent clauses. Thus, the identified option clearly showcases the characteristics inherent to compound-complex sentences, rendering it the best example among the choices provided.