Correct Answer - A::B::C
In 15 s, it will rotate `90^@` or `1/4th` circle .
`:.` Average speed =`("Total distance")/("total time") =d/t`
`=(2piR//4)/15=(piR)/30=(pi(2.0))/30`
`=(pi/15) cm//s`
Average speed =`("Total distance")/("total time") =s/t`
`=(sqrt2R)/t=(sqrt2(2.0))/15=(2sqrt2)/15 cm//s`