Which of the following pairs of ions will have same spin only magnetic moment values within the pair? A. $Zn^{2+}, Ti^{2+}$ B. $Cr^{2+}, Fe^{2+}$ C. $Ti^{3+}, Cu^{2+}$ D. $V^{2+}, Cu^+$. Choose the correct answer from the options given below:

Magnetic moment $\mu=\sqrt{n(n+2)}$ BM. $Zn^{2+}$: n=0, $\mu=0$; $Ti^{2+}$: n=2, $\mu=\sqrt8$; $Cr^{2+}$: n=4, $\mu=\sqrt{24}$; $Fe^{2+}$: n=4, $\mu=\sqrt{24}$; $Ti^{3+}$: n=1, $\mu=\sqrt3$; $Cu^{2+}$: n=1, $\mu=\sqrt3$; $V^{2+}$: n=3, $\mu=\sqrt{15}$; $Cu^+$: n=0, $\mu=0$. So $(Cr^{2+},Fe^{2+})$ [pair B] and $(Ti^{3+},Cu^{2+})$ [pair C] have equal magnetic moments — answer is B and C only.