Q: In this task, you need to answer the given multiple-choice question on geometry. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Problem: find the curved surface area , if the radius of a cone is 21 m and slant height is 15 m ?
Options: ['a ) 660', 'b ) 770', 'c ) 880', 'd ) 900', 'e ) 990']
A:
e