Which of the following elements belongs to the actinoid series?

Which of the following elements are included in the lanthanoid series?

The most basic hydroxide among the following is-

Write a note on oxidation states shown by lanthanoids.

Determine the correct $(T)$ and incorrect $(F)$ statements from the following:
$(a)$ The symbol for Lanthanum is $La$.
$(b)$ The name of the element $Lu$ is Lanthanum.
$(c)$ The electronic configuration of $La^{3+}$ and $Ce^{4+}$ contains $4f^0$.

Which of the following statements is not correct regarding lanthanoids?