Consider the following elements. Which of the following is/are true...

In a group the atomic size increases due to the addition of shells as we move from one period to another. Across a period the atomic size decreases as the number of shells remain the same while the nuclear charge increases. This leads to the pulling of electrons from the outermost shell towards the nucleus thereby decreasing the size.

 Metallic character increases as we move down the group because the atomic size increases which lead to easy loss of electrons. On the other hand, it decreases across a period as we move from left to right. This happens because there is an increase in nuclear charge which makes it difficult for an atom to lose electrons.

In general along the period from left to right, size decreases and metallic character decreases.

In general down the group, size increases and metallic character increases.

${B}^{'} < {A}^{'}$ (size) ${C}^{'} > {A}^{'}$ (size)

${D}^{'} < {C}^{'}$ (size) ${D}^{'} > {B}^{'}$ (size)

${B}^{'} < {A}^{'}$ (metallic character)

${D}^{'} < {C}^{'}$ (metallic character)

${{B}^{'}}^{+} < {{A}^{'}}^{+}$ (size)

${{D}^{'}}^{+} < {{C}^{'}}^{+}$ (size)

$∴$ C statement is incorrect.

Hence ,option B is the answer.