What of the following is characterized by left lower quadrant periumbilical pain in an elderly person, with the presence of fever, tender abdomen, leukocytosis, nausea, and vomiting?

1) Acute appendicitis
2) Diverticulitis
3) Gallstones
4) Pancreatitis

What is the primary cause of hyperphosphatemia in renal failure?

1) Increased dietary intake
2) Decreased renal excretion
3) Increased bone resorption
4) Decreased parathyroid hormone levels

A 20-year-old female presents with a two-day history of fever, sore throat, and a fine, macular rash that appears more prominent on her palms and soles. Which of the following is the most likely diagnosis?
1) Measles
2) Scarlet fever
3) Rubella
4) Mononucleosis