The probability of making a Type $1$ error $($erroneously concluding that the process mean has moved and that the process is no longer in stat control$)$ when using a SPC chart with a 'mean $+-2$ standard deviation' UCL and LCL would be approximately?

$0\mathrm{.}0456$

$0\mathrm{.}0566$

$0\mathrm{.}0027$

$0\mathrm{.}0680$