The Search Time for a Particular Search Term on Google

Multiple Choice

The search time for a particular search term on Google is defined by the probability density function below, where x = the random variable "time to produce a result in milliseconds".Determine the probability that the search will take between 251 and 251.5 milliseconds. 1/5 for values of x between 250 and 255
f(x) =
0 everywhere else

A) .20
B) .156
C) .125
D) .225
E) .10