Which word correctly completes the sentence: 'The _____ reason for the delay was the weather'?

• A. Principle
• B. Principled
• C. Principality
• D. Principal

Answer: (D)

The main idea being tested is choosing a word that describes the reason as the most important one. The word that fits is principal, used as an adjective before the noun reason to mean the main or chief reason. So “the principal reason for the delay was the weather” clearly communicates that weather was the primary cause.

Principle would be incorrect here because it is a noun meaning a rule or belief, not something that can describe a reason. Principled is an adjective meaning morally guided, which doesn’t convey the idea of being the main cause. Principality refers to a territory ruled by a prince, which is unrelated to describing a reason.