Tom, Dorothy, and Sammy went on a vacation and agreed to split the costs evenly. During their trip Tom paid \$ 105, Dorothy paid \$ 125, and Sammy paid \$ 175. In order to share the costs equally, Tom gave Sammy t dollars, and Dorothy gave Sammy d dollars. What is t-d ?

**Answer Choices**

A. 15

B. 20

C. 25

D. 30

E. 35