This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following factors has maximum effect on filtration of a drug by the glomerulus ? 
Select and explain. 
A. Lipid solubility, B. Plasma protein binding, C. Degree of ionization, D. Rate of tubular secretion
B: Plasma protein binding
Answer: B: Plasma protein binding 
Explanation: - Main Factors determining glomerular filtration

   Renal blood flow
   Plasma protein binding

- Lipid solubility does not affect glomerular filtration.
- Ionization determines tubular reabsorption. 
- Tubular secretion happens after glomerular filtration and so does not affect the process.