Step 1: Understanding the question.
Trilobites were a group of extinct marine arthropods. They became extinct during the late Permian period, marking one of the largest mass extinctions in Earth’s history.
Step 2: Analyzing the options.
(A) Devonian: Trilobites did not go extinct in the Devonian period.
(B) Permian: Correct — Trilobites became extinct at the end of the Permian period, during the largest mass extinction event in Earth’s history.
(C) Triassic: Trilobites had already become extinct by the time of the Triassic period.
(D) Cretaceous: Trilobites were long extinct by the Cretaceous period.
Step 3: Conclusion.
The correct answer is (B) Permian, as trilobites became extinct during the Permian mass extinction event.