The set representing the right order of ionic radius is

• A

  $\mathrm{Li}^{+}>\mathrm{Na}^{+}>\mathrm{Mg}^{2+}>\mathrm{Be}^{2+}$
• B

  $\mathrm{Mg}^{2+}>\mathrm{Be}^{2+}>\mathrm{Li}^{+}>\mathrm{Na}^{+}$
• C

  $\mathrm{Na}^{+}>\mathrm{Mg}^{2+}>\mathrm{Li}^{+}>\mathrm{Be}^{2+}$
• Correct answer
  D

  $\mathrm{Na}^{+}>\mathrm{Li}^{+}>\mathrm{Mg}^{2+}>\mathrm{Be}^{2+}$

Hence, the correct answer is option: 'D'.