<image 1> Figure 29-1: Titration curve. Which of the following matches the titration curve shown in Figure 29-1?
['A strong acid is titrated into a weak base.', 'A strong acid is titrated into a strong base.', 'A strong base is titrated into a weak acid.', 'A strong base is titrated into a strong acid.', 'A weak base is titrated into a weak acid.']