I know I'm being really stupid, but I got the same wrong answer twice. Can anyone tell me what to do. Please?

A particle is constrained to move in a circle with 10m radius. Speed is 10m/s, increasing at a rate of 10m/s/s The angle between the particle\s velocity and acceleration vectors is

a) 0

b)30

c)45

d)60

e)90

Thanks in advance,