The probability distribution of a random variable $X$ is given below :X=x 0 1 2 3 P(X=x) $\frac{1}{10}$ $\frac{2}{10}$ $\frac{3}{10}$ $\frac{4}{10}$ Then the variance of $X$ is

Question

$(a)\;1 \qquad(b)\;2 \qquad(c)\;3 \qquad (d)\;4$