The idiom "All that glitters is not gold" means that not everything that looks valuable or promising is actually so.
The correct sentence should be:
"All that glitters is not gold."
Thus, the correct answer is (A) "All that glitters is not gold."
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?