Compute the Variance and Standard Deviation of a Discrete Random

Compute the Variance and Standard Deviation of a Discrete Random Variable
-A seed company has a test plot in which it is testing the germination of a hybrid seed. They plant 50 rows of 40 seeds per row. After a two-week period, the researchers count how many seed per row have sprouted. They noted that least number of seeds to germinate was 33 and some rows had all 40 germinate. The germination data is given below in the table. The random variable x represents the number of seed in a row that germinated and P(x) represents the probability of selecting a row with that number of seed germinating. Determine the standard deviation of the number of seeds per row that germinated. $\begin{array}{|c|c|c|c|c|c|c|c|c|}\hline x & 33 & 34 & 35 & 36 & 37 & 38 & 39 & 40 \\\hline P(x) & 0.02 & 0.06 & 0.10 & 0.20 & 0.24 & 0.26 & 0.10 & 0.02 \\\hline\end{array}$

A) $1.51$
B) $7.13$
C) $36.86$
D) $6.07$