In the radioactive decay of ${\mathrm{}}_{\mathrm{Z}}{\mathrm{X}}^{\mathrm{A}}$ , which of the following could be considered as incorrect statement?

• Correct answer
  A

  $\mathrm{\alpha }-$ decay involves the decrease of both $\mathrm{A}$ and $\mathrm{Z}$ by $2$
• B

  $\mathrm{\beta }-$ decay involves the increase of $\mathrm{Z}$ by one, $\mathrm{A}$ remaining constant
• C

  $\mathrm{K}-$ electron capture results in the decrease of $\mathrm{Z}$ by one with no change in A and emission of $\mathrm{\gamma }-$ rays
• D

  $\mathrm{\gamma }-$ ray emission is followed by the emission of $\mathrm{\alpha }$ or $\mathrm{\beta }-$ particles

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