State true or false.
Given below is an example of a reduction reaction.
${\mathrm{Cr}}^{3+}\to {\mathrm{Cr}}^{6+}+3{\mathrm{e}}^{-}$

Oxidation is the process of giving off electrons. In the oxidation process, the oxidation state or number of an element is increased. In reduction, electrons are accepted and the oxidation number is decreased. 

In an oxidation reaction, either an oxygen atom is added or a hydrogen atom is removed. All oxidation reactions do not, however, always require the addition of oxygen or the removal of hydrogen atoms. Therefore, we also need to define it in terms of contributed electrons.
The oxidation reaction is the process in which electrons are liberated. As a result, the atom often acquires a positive charge as a result of the oxidation reaction.
In the given reaction-
${\mathrm{Cr}}^{3+}\to {\mathrm{Cr}}^{6+}+3{\mathrm{e}}^{-}$
The oxidation state of chromium is changed from +3 to +6, an increase in oxidation number, which means it is an oxidation reaction and not a reduction reaction, so the given statement is incorrect.
Keep in mind that oxidation and reduction reactions happen at the same time. Therefore, for an oxidation reaction to be successful, the reduction reaction must also be occurring at the same time as the oxidation reaction.

Hence, the correct answer is option B