Grouped data — ogive intersection is the median

The ogive more than and ogive less than of the following grouped data

$$\begin{array}{c|ccccc} \text{Class} & 0\text{--}8 & 8\text{--}20 & 20\text{--}30 & 30\text{--}35 & 35\text{--}40\\ \text{Frequency} & 8 & 12 & 18 & 10 & 4 \end{array}$$

intersect at which of the following points?