Final answer:
In hemophilia, the PTT is elevated, the clotting time is also increased due to delayed clot formation, but the platelet count remains normal.
Step-by-step explanation:
In hemophilia, the Partial Thromboplastin Time (PTT) is elevated because the blood lacks sufficient clotting factors, leading to slower coagulation processes. Specifically, hemophilia is characterized by a deficiency in either clotting factor VIII (hemophilia A) or IX (hemophilia B). As a result, the coagulation or clotting time is also increased due to the delayed clot formation. However, the platelet count remains normal because hemophilia does not directly affect the number of platelets, only the function of specific clotting factors. Therefore, the correct answer to the question is (b) up, up, up.