Consider the following pairs of ions:
(1) `Sc^(3+) and Ti^(4+)`
(2) `Mn^(2+) and Fe^(2+)`
(3) `Fe^(2+) and Co^(3+)`
(4) `Cu^(+) and Zn^(2+)`
Among these pairs of ions, isoelectronic pairs would include:

Options

A. 2, 3 and 4
B. 1, 3 and 4
C. 1, 2 and 4
D. 1, 2 and 3

Answer

B