Correct Answer - B
`1 "sin" 90^(@) = mu_(1) "sin"r_(1)`,
`mu_(2) "sin"r_(2) = mu_(1)"cos"r_(1)`
`mu_(2)"cos"r_(2) = mu_(3)"sin"r_(3)`
`mu_(4) "sin"r_(4) = mu_(3)"cos"r_(3)`,
`mu_(4) "cos"r_(4) = mu_(5)"sin"r_(5)`
`1. "sin" 90^(@) = mu_(5) "cos"r_(5)`
Square and add `1 + mu_(2)^(2) + mu_(4)^(2) = mu_(1)^(2) + mu_(3)^(2) + mu_(5)^(2)`