Sam is saving money to buy himself a new phone. He currently has $95. He is able to save about $20 a week. Let represent how much money he has saved, and the number of weeks that have passed since the current date. Choose the correct function rule.

a. s(w) = 95 + 20w
b. s(w) = 95w + 20
c. w(s) = 95s + 20
d. w(s) = 95 + 20s