The correct answer is to. The phrase "blind to" is a fixed English idiom that means unwilling or unable to recognize or accept something—in this case, reason or logic.
Understanding the Idiom "Blind to"
The preposition "to" is used in this context to indicate the direction of someone's inability to perceive or acknowledge something. When a person is "blind to reason," it means they are ignoring or refusing to accept logical arguments, evidence, or sound judgment. They may be stubborn, prejudiced, or emotionally invested in a view that defies rational thinking.
This idiomatic usage extends beyond the literal meaning of blindness. For example:
- "She was blind to his faults." – meaning she refused to see or acknowledge his shortcomings.
- "He is blind to the dangers of his actions." – meaning he does not recognize the risks.
In all these cases, "to" is the correct preposition that links the adjective "blind" to the object of disregard (reason, faults, dangers, etc.).
Why the Other Options Are Incorrect
- of: "Blind of" is not a standard English idiom. While "blind of one eye" is used to describe a physical condition, it is not used with abstract concepts like reason.
- about: "Blind about" is not used in standard English. We do not say "blind about reason" because it does not convey the idiomatic meaning of refusal to acknowledge.
- in: "Blind in" is used for physical blindness (e.g., "blind in one eye") but is not used with abstract nouns like reason.
Therefore, "blind to reason" is the only correct and standard English expression, making "to" the correct answer.