Right choice is (a) SinA/2 = (R2-R1)/(H1+R2-(H2+R2))
Best explanation: When both smaller and bigger ball are inside the groove then the formula to find angle of tapered hole will modify. The modified formula is SinA/2 = (R2-R1)/(H1+R2-(H2+R2)), where A is the angle of tapered hole.