The heights (in cm) of 50 saplings were recorded and the ‘less than’ cumulative frequencies were obtained as follows:
Upper limit (cm):\;5 \;10 \;15 \;20 \;25 \;30 \;35 \;40 \;45 \;50
Cumulative frequency: \;4 \;8 \;15 \;22 \;28 \;35 \;42 \;46 \;48 \;50
Using the cumulative frequency curve, estimate the third quartile Q3 of the heights.
(a) 32.5\text{ cm}
(b) 33.6\text{ cm}
(c) 31.8\text{ cm}
(d) 35.0\text{ cm}