**Core Concept**
Plasma protein binding refers to the reversible association of a drug or endogenous molecule with plasma proteins, such as albumin and alpha-1 acid glycoprotein. This binding affects the pharmacokinetics of drugs, including their distribution, metabolism, and elimination.

**Why the Correct Answer is Right**
Plasma protein binding is a complex process involving hydrophobic interactions between the drug molecule and the protein. The binding sites on albumin are specific and can bind a variety of substances, including drugs, bilirubin, and hormones. The binding capacity of albumin is high, with a maximum binding capacity of approximately 1 g of drug per 100 mL of plasma. This binding can significantly affect the free fraction of the drug, which is the pharmacologically active form.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because plasma protein binding can indeed affect the distribution of a drug to various tissues and organs, including the central nervous system.
**Option B:** This option is incorrect because the presence of plasma protein binding can significantly alter the pharmacokinetics of a drug, including its clearance and half-life.
**Option C:** This option is incorrect because plasma protein binding can affect the toxicity of a drug, as the bound fraction is generally inactive and cannot exert a toxic effect.

**Clinical Pearl / High-Yield Fact**
It's essential to note that plasma protein binding can be altered in various pathological conditions, such as liver disease, nephrotic syndrome, and severe burns, which can affect the efficacy and safety of drugs.

**Correct Answer: A.**