What is the angle between the radial directions of masses A and B?

Question

A disc on a shaft has 3 masses A, B and C . Given m_Ar_A = 8, m_B r_B = m_C r_C = 5. The disc is

perfectly balanced. What is the angle between the radial directions of masses A and B?

            (a) sin^-1(0.6)                 (b) sin^-1(0.625) (c) tan^-1(0.6)    (d) tan^-1(0.625)