Which of the following is not an actinide?

Options

A. Curium
B. Californium
C. Uranium
D. Terbium/Erbium

Answer

D

Explanation

Terbium is lanthanide as it belongs to 4f- series having configuration `[Xe] 4s^9 6s^2`. However the remaining members belong to 5f - series (actinides).