Which of the following is correct

Options

A. Both Assertion (A) and Reason (R ) are true and Reason ( R) is a correct explanation of Assertion (A).
B. Both Assertion (A) and Reason (R ) are true but Reason (R ) is not a correct explanation of Assertion (A).
C. Assertion (A) is true and Reason (R ) is false.
D. Assertion (A) is false and Reason (R ) is true.

Explanation

The reason (R) is clearly true
Now , h=24 cm , R=15 cm and r=5 cm
`therefore l^2=h^2+(R-r)^2={(24)^2+(15-5)^2} cm^2 =(576+100)cm^2=676 cm^2`
`rArr l=sqrt(676)cm =26 cm.`
`therefore` surface area = `pi{R^2+r^2+l(R+r)}`
`=pi{(15)^2+5^2+26xx10}cm^2=pi{225+25+260}cm^2`
`=(510pi)cm^2` , which is true
`therefore` Asseration (A) is true and Reason (R) gives Asseration (A)
Hence , the correct answer is (a)