The correct answer is d) parietals and occipital.
The lambdoidal suture is a fibrous joint that connects the parietal bones to the occipital bone at the back of the skull. This suture is named for its lambda shape, resembling the letter ‘Lambda’ in the Greek alphabet. Understanding the anatomy of skull sutures is essential for those studying human anatomy, as these connections play a critical role in the overall structure and functionality of the skull. The lambdoidal suture typically closes by the time a person reaches adulthood, fusing the bones together securely.