ABC Company wants to increase employee morale. To do so, it implements a contest for employees in the form of a once-a-month drawing for an all-expenses-paid vacation. The company measures employee morale on a sample of 25 employees before the contest has been announced and then again on the same 25 employees after there have been three monthly drawings. The scale used to measure morale can be considered to produce interval level data and the "after" score should be greater than the "before" score if the contest was successful in increasing morale. The most appropriate test for the company to determine if the contest has improved morale would be:
a. One-sample t-test
b. Paired t-test
c. Independent samples t-test
d. ANOVA