Which of the following statements correctly distinguishes between a secant line and a tangent line to the curve y=f(x) at x=a?
a) A tangent line intersects the curve at two distinct points that approach one another, while a secant line touches the curve at a single point.
b) A tangent line gives the average rate of change of f over an interval containing x=a.
c) A secant line intersects the curve at two distinct points, whereas a tangent line touches the curve at exactly one point.
d) A secant line represents the instantaneous rate of change of f at the point x=a."