Correct Answer - B
The refractive index of the material of the prism
`mu=(sin .(A+delta_(m))/(2))/(sin .(A)/(2))`
`impliescot.(A)/(2)=((sin(A+delta_(m)))/(2))/(sin .(A)/(2))`
`sin((A+delta_(m))/(2))=cot.(A)/(2)sin .(A)/(2)`
`sin ((A+delta_(m))/(2))=(cos.(A)/(2))/(sin .(A)/(2))sin .(A)/(2)`
`sin ((A+delta_(m))/(2))=sin ((pi)/(2)-(A)/(2))`
`implies(A+delta_(m))/(2)=(pi)/(2)-(A)/(2)`
`A+delta_(m)=pi -Aimpliesdelta_(m)=180-2A`