From the given options, choose the one word which will correctly replace the expression.

"Fundamental truth or proposition"

Principle

The correct answer is Option 2: Principle

The word that correctly replaces the expression "fundamental truth or proposition" is principle. A principle is a fundamental truth or proposition that serves as the foundation for a system of belief, behaviour, or reasoning.

• Principal :As a noun, "principal" refers to the head of a school or college, or a sum of money lent or invested on which interest is paid. As an adjective, "principal" means first in order of importance; main.
• Prime meridian means "the imaginary line that passes through Greenwich, England, and is used as the basis for measuring time around the world."
• Primate means "a member of the order Primates, which includes humans, apes, monkeys, and lemurs."