What are the different types of samples used in clinical biochemistry?

I- Blood is the most commonly used biological fluid for clinical analysis.
II- Urine is especially suitable for tests that evaluate renal function and for metabolites that are quickly cleared from the bloodstream and accumulate in urine, such as drugs.
III- Other fluids, such as amniotic fluid, synovial fluid, peritoneal fluid, pleural fluid, and pericardial fluid, are used in limited clinical settings and are analyzed exclusively for a few special analytes.
IV- Saliva is a sample whose composition reflects the levels in the blood plasma of many low molecular weight substances, such as drugs or alcohol.
a) Only I and II are correct.
b) Only III and IV are correct.
c) All statements are correct.
d) None of the statements are correct.