Which of the following is an example of a complex sentence?

A complex sentence is defined as one that contains an independent clause and at least one dependent (or subordinate) clause. The correct example, which is the sentence stating, "When I ride my bike along a country lane, I feel a harmony with the world around me," demonstrates this structure effectively.

In this sentence, "I feel a harmony with the world around me" is the independent clause; it can stand alone as a complete thought. The beginning part, "When I ride my bike along a country lane," serves as the dependent clause, providing additional context but unable to function as a complete sentence on its own. This combination showcases the features of a complex sentence, effectively linking related ideas while emphasizing the relationship between riding the bike and the feeling of harmony.

The other options either present simple sentences, which consist of a single subject-predicate pair, or do not include the required dependent clause to qualify as complex. For example, statements like "I so enjoy riding my bike" and "The simplicity of the movement and the peacefulness of the countryside offers serenity" are complete thoughts with just one clause. Therefore, the correct response exemplifies the complex sentence structure required.