Which of the following statements related to vectors is not correct?
a) A "one way" road sign is an example of a vector.
b)A vector is a physical description that includes both a number and a direction.
c)If someone states, "Joe is traveling at 30 miles per hour, due east, on Dansbury Road." you can describe Joe's velocity as a vector.
d)The following information is insufficient to to describe a ship's velocity as a vector: "A ship is traveling north by northeast at a rapid speed."
I'm stuck between a and d.