Two Events Occur 100 M Apart with an Intervening Time $\mu$

Multiple Choice

Two events occur 100 m apart with an intervening time interval of 0.60 $\mu$ s.The speed of a reference frame in which they occur at the same coordinate is:

A) 0 c
B) 0.25c
C) 0.56c
D) 1.1c
E) 1.8c