In +2 Oxidation state, Which of the following lanthanoids act as reducing agents?

A good reducing agent oxides itself readily. Eu and Yb act as reducing agent in +2 oxidation state by using two electron and forming Eu²⁺ and Yb²⁺, these will get stable half – filled $\left[xe\right],4f^7$and fully-filled $\left[xe\right],4f^{14}$ )
Configuration respectively.