At x=3 the graph of a function y=f(x) shows an open circle at the point (3,5), while the curve approaches height 5 from both sides and no other point is plotted on the line x=3. What kind of discontinuity does f have at x=3?
a) Infinite discontinuity
b) Jump discontinuity
c) Removable (point) discontinuity
d) The function is continuous at x=3