Correct option is: A) 7040
Given that d = 40 cm
\(\therefore\) r = \(\frac d2 = \frac {40}2 = 20 \, cm\)
h = 56 cm
\(\therefore\) Curved surface area of cylinder = \(2 \pi rh\)
= 2 \(\times\) \(\frac {22}7\) \(\times\) 20 \(\times\) 56 = 44 \(\times\) 160 = 7040 \(cm^2\)
Hence, the curved surface area of cylinder is 7040 \(cm^2\)