The word "immaculate" means something that is perfectly clean or free from any flaws or stains.
The correct synonym for "immaculate" is "spotless", which also means completely clean.
The words "dull", "healthy", and "modern" are not related in meaning to "immaculate".
The correct answer is "spotless".
Arun’s present age in years is 40% of Barun’s. In another few years, Arun’s age will be half of Barun’s. By what percentage will Barun’s age increase during this period?