A college student is saving money to buy a laptop. the student has $85 saved and saves $35 each week. The function a(t)=35t + 85 represents the amount of money the college student has saved for the laptop after t weeks. The student receives $50 as a birthday gift . If the function f(t) = a(t) +50 represents the total amount the student has saved , which best describes the transformation from a(t) to f(t)?