Two particles A and B are moving in uniform circular motion in concentric circles of radii `r_(A)` and `r_(B)` with speed `u_(A)` and `u_(B)` respectively. Their time period of rotation is the same. The ratio of angular speed of a to that of B will be:
A. `1:1`
B. `r_(A):r_(B)`
C. `upsilon_(A):upsilon_(B)`
D. `r_(B):r_(A)`