Sachin score 140 runs by hitting 7 6's and 20 4's. How many runs did he score by running between the wickets?

Question

$\begin{array}{11} (a)\; \text{20 runs} \\ (b)\; \text{18 runs} \\ (c)\; \text{25 runs} \\ (d)\; \text{21 runs} \end{array} $