[Select all that apply] Given a function y = f(x), what is the geometric interpretation of f'(a)? (a.) f'(a) is the slope of the tangent line to the graph of f at x = a. (b.) f'(a) is the slope of the secant line to the graph off at x = a. (c.) f(a) is the slope of the tangent line to the graph of f at any given point. (d.) f(a) is the limit of f(x) at x approaches h. U Ob a U U C