Four different forecasting methods were applied to a set of time$-$series data. The root$-$mean$-$square error $($RMSE$)$ was calculated for each method. Which of the following four RMSE values would be associated with the forecasting method that fit the data set best?

A$.$

$2\mathrm{.}00$

B$.$

$1\mathrm{.}96$

C$.$

$2\mathrm{.}33$

D$.$

$6\mathrm{.}21$