[单选题]
99.01: The change of distance per8kd 7ovux7az , w j cvpg,rw14x5li.q8 unit time withou*(w(rf x(tzu jqetb v xa7a,g),2oy t9t reference to a particular dit x oax9 u7,vbw( fa yj)tt*(g(er2zq,rection is called
A. inertia
B. speed
C. velocity
D. acceleration
E. position