What is the difference between a full agonist and a partial agonist at nicotinic receptors?

What is the difference between a full agonist and a partial agonist at nicotinic receptors?

• A. A full agonist stimulates receptor to the same extent as nicotine; a partial agonist fails to activate receptors at all.
• B. A full agonist blocks nicotine's action; a partial agonist enhances nicotine's effect.
• C. A full agonist fully stimulates receptor; a partial agonist stimulates receptor to a lesser degree and blocks nicotine's full effect.
• D. Both act identically on receptors.

Answer: (C)