Ans: D
According to the box-and-whisker diagram, the lower quartile is $50$ marks. Then, there are $75\%$ students of the class getting marks higher than $50$ marks.
According to the box-and-whisker diagram, the lower quartile is $50$ marks. Then, there are $75\%$ students of the class getting marks higher than $50$ marks.
Hence, the passing percentage of the class is $75\%$.
