The statistics of runs scored in a series by four batsmen are provided in the following table. Who is the most consistent batsman of these four?
$$\begin{array}{|c|c|c|}\hline \text{Batsman} & \text{Average} & \text{Standard deviation} \\ \hline \text{K} & 31.2 & 5.21 \\ \hline \text{L} & 46.0 & 6.35 \\ \hline \text{M} & 54.4 & 6.22 \\ \hline \text{N} & 17.9 & 5.90 \\ \hline \end{array}$$
- K
- L
- M
- N