In Chapter $13,$ Jack Davis describes how Nash Roberts was able to predict the timing of hurricane Audrey when the Weather Bureau got it all wrong. What was one clue that he used to support his forecast, as mentioned in the book?

a$.$ The high pressure system north of Audrey was weakening, which meant that the storm's pace would pick up and it would reach land much earlier than the Weather Bureau predicted.

b$.$ He logged reports from ships and oil platforms that indicated the storm surge was approaching $18$ feet, almost twice as high as predicted by the Weather Bureau.

c$.$ He felt it was necessary to determine a storm's personality; Audrey was very chaotic, leading him to widen the forecast cone to encompass far more coastal cities than the Weather Bureau included in their warning.

d$.$ He took off in an airplane and flew into the storm, taking coordinates to track its direction and speed, which let him know it was moving in a different direction than the Weather Bureau predicted.