Two masses M1 and M2 are tied together at the two ends of a light inextensible string that passes over a frictionless pulley. When the mass M2 is twice that of M1. the acceleration of the system is a1. When the mass M2 is thrice that of M1. The acceleration of The system is a2. The ratio \(\frac{a_1}{a_2}\) will be:

(A) \(\frac13\)
(B) \(\frac 23\)
(C) \(\frac32\)
(D) \(\frac 12\)