The radius of ${\mathrm{La}}^{3+}$ is $1.06\text{Å}$ which of the following given values will be closest to the radius of ${\mathrm{Lu}}^{3+}$

(At. no. of $\mathrm{Lu}=71, \mathrm{La}=57$)?

Lanthanides are characterized by a decrease in atomic/ionic size with an increase in atomic number. Therefore, ${\mathbf{Lu}}^{\mathbf{3}\mathbf{+}}$ ionic radius will be less than ${\mathrm{La}}^{3+}$ ionic radius. It won't be 1.06 A or more. As a result, option D, $0.85\text{Å}$, is the appropriate response.