My father remains inflexible once he has taken a decision

Analyze the question: You are asked to find the word closest in meaning to inflexible in the sentence: "My father remains inflexible once he has taken a decision."

Explain the concept: "Inflexible" comes from in- (not) + flexible (able to bend or change). When used for a person, it means someone who will not change their mind or position, even when pressured. It is a synonym of rigid, firm, stubborn, unbending and unyielding.

Step-by-step solution:

• A. certain: This means sure or definite. A person can be certain without being unwilling to change, so it doesn't capture the idea of refusing to bend.
• B. relaxed: This means calm or easygoing. It is nearly the opposite of inflexible.
• C. permanent: This describes things that last forever, such as a permanent job. It is not used for a person's attitude, and it doesn't mean "unbending."
• D. unyielding (spelled "unyeilding" in the question): This means refusing to give way or change. It matches "inflexible" exactly. The sentence says the father does not change his decision once it is made, which is being unyielding.

Answer: Option D.

Tip: When you meet a word with a prefix like in-, un- or im-, break it apart. In- + flexible = "not bendable." Then look for the option that means "not bending," which here is unyielding. Also, a good synonym often looks like the opposite of the antonym: relaxed (B) is close to the antonym, so you can eliminate it quickly.