At a certain company, each employee has a salary grade s that is at least 1 and at most 5.  Each employee receives an hourly wage p, in dollars, determined by the formula p = 9.50 + 0.25(s – 1).  An employee with a salary grade of 5 receives how many more dollars per hour than an employee with a salary grade of 1?

A.     $0.50

B.     $1.00

C.     $1.25

D.     $1.50

E.      $1.75